Friday night I think I experienced this same bug.
Settup: Was upping for a long distance fighter escort to rondevou with a squadie in buffs over the Rook strats in a P-51D, 100% internal and 2x75gl externals. Target altitude was 24k.
Execution:
-Spawned on medium airfield NE runway (if you need the field # I can look it up), set manual fuel select to Aux, WEP T.O., turned to autoclimb heading East.
-WEP climbout until (I think?) ~50% Aux fuel tank and turned WEP off manualy. Continued autoclimbing on manual Aux fuel until ~33% remaining (typicaly I aim for a hair above 3/8ths on the guage), re-cycled to auto-fuel management.
-Still autoclimbing East, I (think I) was above 14k with 10k to go, I remember deliberatley checking that auto-fuel management was back on and that it was feeding from my full externals. I went AFK for a smoke outside, sometime between then and returning I had discoed from the server.
The problem:
Upon reconnecting my aircraft was in a state of full internal fuel stores, one external tank jettisoned, and the remaining tank with ~70gls of fuel left.
This is not so much a problem as it is an inconvenience when all things are considered, but I do see a potential to limitedly exploit it (fly light internal and full external inbound, to be in a better state of preparedness incase enemy intervenes, if not then after your internal stores are too low, you induce a disco and refuel your internals from the externals.).
