It doesn’t seem to matter which fuel I use. The vanilla turrets work as normal, but the advanced flamethrowers don’t leave flames on the ground. They shoot and kill biters, just not sticky flames. I can’t tell if it’s just a visual bug or if the effect is completely absent.

I’m also using Modular Turrets, but that’s it as far as I know for mods that should affect turrets, and that mod doesn’t have any flame turrets.

This was intentional. The turret was spawning so much fire that even one would cause lag unless the biters were somehow killed immediately.
Even now, 5-10 turrets can significantly reduce the UPS, but this is much better than what it was.

To compensate for the potential loss of fire damage, direct damage has been increased several times and area damage has been added.

Oh awesome! Glad to know everything is working correctly.

Thanks so much for doing all this! Really enjoying it