Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/test/miner_tests.cpp`:
- Around line 583-584: Extract a small helper (e.g. AgeTxForInstantSend) near
the top of the test file or inside MinerTestingSetup that wraps the repeated
call to m_node.clhandler->UpdateTxFirstSeenMap by computing the epoch seconds
via
std::chrono::duration_cast<std::chrono::seconds>(Now<NodeSeconds>().time_since_epoch()).count()
and passing (base_time - WAIT_FOR_ISLOCK_TIMEOUT), provide an optional base_time
parameter defaulting to the current epoch seconds, and replace all repeated
direct UpdateTxFirstSeenMap(..., Now<NodeSeconds>()... -
WAIT_FOR_ISLOCK_TIMEOUT) calls with AgeTxForInstantSend(txid_set) to reduce
duplication and improve readability while keeping existing semantics.

These findings are from an automated code review. Verify each finding against the current code and only fix it if needed.

In `src/instantsend/instantsend.cpp`:
- [BLOCKING] lines 469-475: Removing the blockchain-sync gate makes block acceptance depend on pre-sync ISLOCK state
  This method used to disable conflict rejection until masternode sync had reached the blockchain-synced stage, which kept transient InstantSend state out of `ConnectBlock`. After this change, `validation.cpp` calls `ShouldInstantSendRejectConflicts()` and returns `conflict-tx-lock` for any locally known conflicting lock, while `NetInstantSend::ProcessMessage()` still accepts and queues incoming ISLOCKs without checking `IsBlockchainSynced()`. A node that is still catching up can therefore learn a conflicting ISLOCK from the network and reject an otherwise valid block before it has finished syncing, which is a behavioral regression in the block-validation path.

Verify each finding against the current code and only fix it if needed.

Outside diff comments:
In `@src/test/miner_tests.cpp`:
- Around line 159-163: The test computes hashLowFeeTx (via tx.GetHash()) and
adds it to the mempool with
m_node.mempool->addUnchecked(entry.Fee(feeToUse).FromTx(tx)) but never backdates
that mempool entry, so the subsequent
AssemblerForTest(...).CreateNewBlock(scriptPubKey) may exclude it due to
InstantSend safety timeout instead of exercising the min-fee package logic; fix
by setting the mempool entry time before adding (e.g. use the CTxMemPoolEntry
builder's Time(...) or equivalent on the same `entry` used for FromTx(tx)) to a
value older than the InstantSend safety window so hashLowFeeTx is aged and
evaluated by the min-fee package logic when CreateNewBlock is called.

These findings are from an automated code review. Verify each finding against the current code and only fix it if needed.

In `src/masternode/sync.cpp`:
- [SUGGESTION] lines 14-15: NullNodeSyncNotifier silently stops enforcing its invariant in release builds
  The new stub is documented as keeping `CMasternodeSync` permanently unsynced for chainstate-only contexts, but these callbacks only do `assert(false)`. Under `-DNDEBUG` they become no-ops, so `CMasternodeSync::SwitchToNextAsset()` can still advance `nCurrentAsset` to `MASTERNODE_SYNC_FINISHED` before `SyncFinished()` runs. That means the newly added stub does not actually guarantee `IsBlockchainSynced()==false` / `IsSynced()==false` in production builds, which defeats the contract described in `sync.h`. If this notifier is used for the planned chainstate-only path, release builds can accidentally re-enable network-dependent validation gates that were supposed to stay off.

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@src/masternode/sync.h`:
- Around line 35-41: The doc comment for the chainstate-only stub overstates its
guarantee by saying CMasternodeSync "permanently" returns
IsBlockchainSynced()=false and IsSynced()=false; change the wording to a softer
statement such as "expected in chainstate-only usage" and note that
SwitchToNextAsset() can advance sync state (e.g., to MASTERNODE_SYNC_GOVERNANCE)
before notifier asserts, so IsBlockchainSynced()/IsSynced() are not strictly
guaranteed to be permanently false; keep the note that any actual sync
advancement should use a real notifier (NodeSyncNotifierImpl) and that the stub
asserts on calls.

---

Outside diff comments:
In `@src/test/miner_tests.cpp`:
- Around line 309-324: The two transactions added with
m_node.mempool->addUnchecked (the parent and the child around tx.GetHash()/hash)
are un-aged so IsTxSafeForMining rejects them; before each addUnchecked call
call m_node.clhandler->UpdateTxFirstSeenMap({hash}, pblocktemplate->block.nTime
- WAIT_FOR_ISLOCK_TIMEOUT) using the transaction hash computed by tx.GetHash(),
then proceed with entry.Fee(...).FromTx(tx). This ensures the txs are aged for
mining checks (see UpdateTxFirstSeenMap, m_node.clhandler, addUnchecked,
IsTxSafeForMining, pblocktemplate, WAIT_FOR_ISLOCK_TIMEOUT).

These findings are from an automated code review. Verify each finding against the current code and only fix it if needed.

In `src/validation.cpp`:
- [SUGGESTION] line 2615: `!IsInitialBlockDownload()` is not equivalent to the old `RejectConflictingBlocks()` gate after a sync reset
  Pre-PR, this islock-conflict check only ran when `CInstantSendManager::RejectConflictingBlocks()` returned true, which in practice required `CMasternodeSync::IsBlockchainSynced()` to be true. The replacement `!IsInitialBlockDownload()` is not equivalent: `CChainState::IsInitialBlockDownload()` latches to false permanently (`src/validation.cpp:1715`), but `CMasternodeSync` can be reset back to `MASTERNODE_SYNC_BLOCKCHAIN` after a long sleep / lost-tip condition (`src/node/sync_manager.cpp:154-158`, `src/masternode/sync.cpp:27-44`). During such a resync window, `NetInstantSend::TransactionAddedToMempool` and `BlockConnected` (`src/instantsend/net_instantsend.cpp:432, 522`) still skip IS processing because they check `IsBlockchainSynced()`, yet `ConnectBlock` will now reject any block that conflicts with whatever islocks happen to be persisted in `CInstantSendDb`. This is arguably more correct (signed islocks don't go stale, and the `has_chainlock` override is preserved), but the PR description does not document the change and there is no functional test exercising a freshly started or post-reset node receiving a chain that conflicts with persisted islocks. Either add a regression test or note the semantic widening explicitly in the commit message.

In `src/masternode/payments.cpp`:
- [SUGGESTION] lines 161-172: `IsOldBudgetBlockValueValid`: switch to `IsValidAndSynced()` relaxes the strict path when governance failed to load
  Pre-PR the strict reward check at this site triggered on `m_mn_sync.IsSynced()` alone; the new `m_govman.IsValidAndSynced()` is `is_valid && IsSynced()`. On a fully-synced node where governance failed to load (`is_valid==false`), the old code still ran the strict check, while the new code falls through to the permissive 'rely on online nodes' path. The PR description only justifies the equivalence at the `IsBlockValueValid`/`IsBlockPayeeValid` sites — the change here is a real (small) relaxation. In practice the path is mostly dead on mainnet (the window is `nBudgetPaymentsStartBlock` to `nSuperblockStartBlock`), but it is reachable on devnet/regtest. Either preserve prior behavior (`m_govman.IsValid() ? m_govman.IsValidAndSynced() : m_mn_sync.IsSynced()`) or call out the intentional behavior change in the commit message.

These findings are from an automated code review. Verify each finding against the current code and only fix it if needed.

In `src/masternode/sync.cpp`:
- [SUGGESTION] lines 14-15: NullNodeSyncNotifier uses lowercase assert(false) — compiled out under NDEBUG
  The header at src/masternode/sync.h:35-41 documents that NullNodeSyncNotifier 'asserts on any call — if sync state is being advanced, a real notifier (NodeSyncNotifierImpl) must be used instead.' The implementation uses the C `assert()` macro from <cassert>, which expands to nothing when NDEBUG is defined. Release builds of dashd define NDEBUG (only `--enable-debug` clears it), so in release builds these methods silently return rather than abort. If a chainstate-only context wired with NullNodeSyncNotifier ever routes a call into CMasternodeSync::SwitchToNextAsset() or Reset(true, /*fNotifyReset=*/true), the stub will silently no-op and the documented invariant will be violated. Use Bitcoin Core's `Assert()` from util/check.h, which survives NDEBUG.

In `src/node/miner.cpp`:
- [SUGGESTION] lines 381-385: Removing RejectConflictingBlocks() gate changes mining behavior beyond the unit tests
  Pre-PR this gate was `RejectConflictingBlocks() || !IsInstantSendEnabled() || IsLocked(txid)` — the first clause returned `m_mn_sync.IsBlockchainSynced()`, which short-circuited the IsTxSafeForMining check until masternode/blockchain sync had progressed past the blockchain stage. That sync gate also protected callers that don't wait on mn_sync: the hidden mining RPCs (`generateblocks`, `generatetoaddress`, `generateblock`) call BlockAssembler::CreateNewBlock() directly (src/rpc/mining.cpp). On regtest/devnet or any isolated InstantSend-enabled node, freshly submitted mempool transactions will now be silently filtered out of mined blocks until they are 10 minutes old or manually IS-locked. The numerous `UpdateTxFirstSeenMap(..., now - WAIT_FOR_ISLOCK_TIMEOUT)` additions in src/test/miner_tests.cpp are direct evidence the change affects real assembly behavior, not just a test harness quirk. Either gate this on `!IsInitialBlockDownload()` (to mirror the new ConnectBlock gate) or document/test the regtest impact explicitly.