Ok this is way harder to reproduce than I have expected. I have experienced this in multiplayer on High Forts, as well as in campaign in Nashpvos mission (as I have tried to snipe the BB with ravens there, and all that achieved was many dead ravens (as they'd overshoot the target and try to turn around for actual attack run, but by that time they'd die to AA). However, when I try to recreate this in a controlled environment (http://zero-k.info/Battles/Detail/1748111) the ravens do derp visually (i.e. bump into terrain like silly flies) but that does not result in any loss of tactical ability (i.e. they still hit the target just fine). In the entire replay I've managed to have 2-3 of them get confused and overshoot the target, but that is quite tolerable. I'll keep trying to reproduce this reliably, if I manage I'll post here.
AFAIK the unit AI and pathing is part of sync code, so any factor like CPU load should not affect it, right? Or is there some unsynced code there as well? In this case may be it glitches when the code doing the unit AI lags behind the simulation?
Another aspect is, if the target is under shields, should ravens dive under the shield to bomb it? There used to be a toggle for that, but now it does not appear to be present. What is the intended behavior?