[bug] cosmic-greeter battery percentage freezes at 100% during threshold discharge, only updates when charging resumes

[nuwngmax-boop]

Environment

• OS: Pop!_OS 24.04 LTS (COSMIC Desktop)
• Component: cosmic-greeter (Lock Screen / Display Manager)

Describe the Bug

When using battery charge thresholds (where the laptop runs on AC power and the battery slowly discharges over days down to the threshold, e.g., 85%), the lock screen (cosmic-greeter) battery percentage stays completely frozen at 100%.

It only updates when the battery actually drops below the threshold and active charging begins. Meanwhile, the main desktop panel battery indicator works perfectly fine.

Steps to Reproduce

1. Keep the laptop plugged into AC power continuously with a charge threshold enabled (so the battery slowly drains over days, e.g., dropping down to 85%).
2. Observe that the main desktop panel accurately shows the decreasing battery percentage.
3. Lock the screen while it's discharging — cosmic-greeter stays stuck at 100%.
4. Once the battery hits the threshold and officially starts charging again, check the lock screen.

Expected Behavior

The lock screen battery percentage should match the desktop panel and update dynamically in real-time as the battery level changes, regardless of whether it's holding a charge threshold or discharging.

Actual Behavior

• Desktop Panel: Works completely fine (accurately shows battery drain over days while plugged into AC and charging status).
• Lock Screen (cosmic-greeter): Freezes at 100% throughout the entire multi-day discharging phase while plugged into AC.
• The Trigger: The moment the battery drops to the threshold (e.g., 85%) and active charging kicks back in, cosmic-greeter instantly jumps/updates to 85% and correctly tracks up to 100%, where it freezes again.
• Conclusion: cosmic-greeter fails to update during slow threshold-based discharges while plugged in, and only refreshes when an active charging state event occurs.