Altitude stuck

[slimatwar]

Watch flight 4801(the 2 Buccaneers). The group's altitude is stuck to 300 ft, no matter what the set is.I've seen this happening in many scenarios.I've tried to unassign group and set different altitude but nothing changes.
Build 1728.2

[Knightpawn]

It happens occasionally (much less in the 1728 built), but I am unable to discern a pattern causing it.

The way to manually fix it is to unassign from mission, order RTB (at which point the aircraft will start gaining altitude), then unassign again and assign to its original mission anew.

[Roller]

I have also seen this with manually controlled Cold War US Canberras. They are stuck to the altitude and speed, seemingly of their loadout's final attack alt and speed.