Recipe added initially works but then drops to 0%

[il13h]

This behavior seems like it may be an issue, but I may also have misunderstood something.

I have a block here (py modpack) where the main product is pitch (black barrel), which is made on the top row from tar (green droplet).

I initially added the three recipes on rows 3, 4 and 5, which all produce tar. I needed to switch to matrix solver. Works fine this far.

Then, I realized those 3 recipes also make coal gas (pale yellow flame), which in turn can be made into tar and syngas (orange flame). So I clicked on the coal gas product and added the recipe and moved it to row 2. This worked fine and I was happy with the block.

However, minutes later when I opened the block again, recipe on row 2 was at 0 inputs and 0 outputs, and all the tar was again sourced from rows 3, 4 an 5. Manipulating the recipe order, removing or adding the row 2 recipe, manipulating the + an - signs did not seem to help.

What did help was explicitly adding syngas (orange flame icon, side product of line 2 recipe) as an output of the block. I did not even need to specify an exact amount, as soon as I put it in as an output, row 2 again adjusted to use up all coal gas to make tar. Screenshot is from this position. If I click on syngas in outputs, set it back to 0, then row 2 again drops to processing nothing, and does not contribute to tar input on row 1.

So in short: added recipe worked at first, but then stopped contributing seemingly with no changes. Adding side product of recipe as an output of the block is a workaround, for some reason.

[il13h]

This is with 2.0.72 and 2.2.5 Helmod. There are no syngas or coal gas recipes on parent blocks. I can provide the "Upload production line" string if needed.