It's not a bug, it's how the FC3 planes fly.
The A-10c is code with the AFM (advance flight model) wich is why it doesn't behave like that. FC3 planes are code with a SFM(standanrt flight model) wich is way simpler. And it's not going to chance, as writting an AFM take a huge amount of time.
The A-10a from FC3 in a next patch, will have the same AFM as the A-10C, beeing the only FC3 plane to have an AFM
EDIT: I didn't saw danilop's answer..... ninja'd