Bad practice to raise flaps in the turn. Reason is, you have very high lift devices deployed. raising them in the turn is a no no on a heavy or high performance jet.
Your general statement is inaccurate.
I've been raising and lowering flaps in turns for 12 years in heavy 747s (all varieties), and haven't had one stall or fall out of the sky yet. Performance margins are more than adequate in all normal flight conditions -- maybe that's why the 747 FCOM and Flight Handbook say it's allowed...