To expand the record, I have experienced this at both VIR and Summit Point Main. I have a 330i ZHP sedan, and it occurs around 3/8 tank. On both tracks it happens out of Turn 1 coming off the main straight. At Summit Point is does not happen at 6a/6b, which is also a long right hander - almost 270deg. Maybe the hard braking coming off the main straight is a contributing factor. 6a/6b comes after hard braking into a left hander at Turn 5.
Anyway, thank you e46fanatics for the wisdom. Looks like I need to order an M3 fuel baffle.
'04 BMW 330i ZHP
'08 Audi TT Roadster
'13 Land Rover LR4