When adding HeroTurrets to a game in progress I had some Flamethrower turrets instantly level (as they had over 150 kills) to PFC
They then proceeded to completely drain 60k Heavy Oil stored in tanks almost instantly when firing
Removing them and re-placing them had the same issue
Downgrading to normal Turrets fixed the issue (as did removing HT_R), and any turrets that levelled from then on did not have this issue (on further testing this is not true, it happens when some turrets upgrade. I cannot figure out any pattern to it). I had a look through the source code and can't see an obvious cause...
The only overhaul mod I'm using in this game is Warptorio 2 Space Age - but that doesn't have any interactions with turret behaviour

Idk why this generated a second comment...

A bit of further testing:
It appears to occur at the moment of upgrading, possibly related to the 2.0 fluid changes?
when I commented out the "re-add in fluid" code in local_replace_turret - the bug no longer occurs

    if fluid ~=nil then
        for k = 1, #fluid do fb = fluid[k]
            --new_entity.fluidbox[k] = {name = fb.name, amount = fb.amount, temperature = fb.temperature}
        end
    end