Totally forget I made this thread but for anyone who may stumble across this thread I thought I would post the solution.
Leaving the APU on especially after take off is generally the cause of this issue. I have speculated on possible reasons why this is (bleed air valve closing, APU gen shutting off cooling fan for the apu, etc etc), but I won't list them all here since I am far from an A-10C expert lol. The manual does mention something to the effect of shutting down the APU before take off.
So my general rule of thumb is double check that the APU and APU gen are off before doing your run up to 80.
Honestly just following the normal startup procedure and turning it off as instructed is the best approach since we never do ground power starts with the A-10 in DCS anyway. But if for some reason you followed the ground power startup procedure then double checking the APU before run up is a good back up habit to have!
CrypticVillain's post in Random Engine Fires was marked as the answer