I can just give mustard to it, the awkward swaying is as old as IL-2,
I have it in DBW and seen it on UP3 server and BAT 4.1.2. too.
Is not aircraft.type specific, it is most to Player flight.
If you observe your Flight AI #3, #4, seldom #2, than it's a signal for silly things to come.
Can happen if Player paces the Throttle and goes fast or zoom climbs like an idiot,
had it soon after T/O or in any situation ingame.
where it gets more frequently is when they are trapped at the waypoint after Target set to Groundobject or ship.
That should be a warning point, that is when AI hangs, at this stage the frequency is highest to get that bug.
Using rejoin doesn't help always to overcome, as does when you simply wait for them to end that fashion.
If they come out of waypoint circling they sway roll left and right. in very rare occassions if #3 and #4 are rolling, they
can collide in a midair crash, I had it that I lost even my Wingman over the 2nd Pair doing silly things with it.
Sometimes they stop from alone, sometimes I need to toggle Formations to break that routine they are trapped.
Break, get into formation, Break, use a another Formation. Once you use Formation call it's safe.
It seems to override these awkward bugs, I found that in my
Pedestal Malta QMBs, the only long waypoint Missions I fly frequently.
But for people not pedantic over having nerves for caring about stupid AI, if
situation allows, send them back to base.