Do you have any Steps? I am unable to repro this issue.
i specifically had it happen with the m8 scott but the steps are give it a move order and then tell the crew to bail. i was giving relatively short move orders (i'm guessing 30-40m, it all happened on one screen) and it was in combat on all occasions.
Decrewing a USF vehicle while it's moving causes the vehicle to finish the move order and then the crew to bailout. during this time the vehicle is uncontrollable. i'm sure this is how crews can be bailed from an out of control vehicle.
i think there are few people who really disagree with you. every couple of months one of the specific artillery threads turns into a more general thread and i'll say here what i say in those.
changing artillery so that it has a smaller lethal (>=80) AoE but a higher AoE that does significant damage to infantry (say, 20-60 damage) would be good because it allows artillery to inflict bleed without causing as many wipes but still allows artillery to do damage to vehicles, emplacements, and infantry with a direct hit.
as far as mortars go, i've always thought it would be a nice feature if barrages got more accurate the longer they went on. it's more realistic (for those who care) and it allows mortars to do more damage to stationary targets while still give mobile units time to move. at the moment artillery is frustrating for both the user and the person on the receiving end because it will sporadically wipe squads but other times miss an entrenched target multiple times.
this actually doesn't "need" a hotfix since it effects everyone mostly equally. it makes particular units more or less attractive but it doesn't explicitly favour one faction over another.
of course, it's still a core part of the game missing.