[III/JG53_Don]

It isn't just a problem of weak mission building imho.
I built a mission myself in which I comand the AI 109 to escort Do17 to their targets. I repeat the escort command for every following waypoint, but as soon as some Hurricanes attacking the bombers, the 109 are engaging..... fighting for some poor minutes and then heading home, leaving the whole bomber group alone on the whole upcoming flight and ignored the next waypoints totally.
One time the whole bomber group on the other side began to dive randomly after being attacked by the Hurris and made a huge right turn, allthough only 1-3 bombers were damaged a little.

It shows that there are some general (and I won't say minor) problems with the AI behaviour.