That Bombers do weird defensive tricks came with the super better 4.12m TD AI update.
Has nothing to do with class defined Fighters, Bombers, Sturmovik as per Class definition.
It's a new occuring random Trigger on any AI Aircraft also set on Bombers.
Attack them head on, somewhere there is a trigger.
When coming from behind this is not so often.
If you watch this on a Me Gigant, you know that 4.12AI is at some stages, funny.
All the world was blabbering about B'N'Z, now you got it, crap 4.10m AI gone, that was the worst we ever had.
Now a B-17 can fliproll, nice.
I saw this happening in B.A.T., CUP, TFM412, even in UP3.4 Cassie, any 4.12 based Mod Game Pack suffers from this.
Previously to 4.12m I've never seen stuff like that before.
Sometimes it get's messed up with older defects in AI code.
What is still an old Bug, from ancient times, that Wingmen 3,4, in rare cases 2, do such stuff flip rolling 1000m up and down as there's a bug in the rejoin,
stay in Formation code. 2008-2009 we discussed that and how to prevent, with KiwiBiggles over at Mission4Today.
There's a fine Tutorial about the AI Commands over there.
Happens not just in Player's Army, but it can be at enemy side AI too. Player side is controllable.
Best wishes
Tobias