Fire chance on the M20 API-T

does anyone feel like the fire chance on the latewar tracer belts of the M2 50cal is practically lowered?
I’ve been hit by american fighters?
no fire
sprayed an enemy fighter with my american fighter?
no fire
Check the replay hit analysis? 90% of shots decimating the engine

tried russian 50cals
still same fire chance with tracer belts

tried italian 50cals
still same fire chance with tracer belts

I checked earlier belts and found to create more fires with the ground belts, specifically engine fire.
Did I miss some patchnotes saying that they nerfed Incendiary rounds? or am I just imagining things?

is this are or ground belts, as i can tell you now any ground 50cal is setting you on fire the moment a round hits your engine or fuel tanks.