Not sure if this an AI issue or something due to the recent flight model changes or both. This issue has become far worse since the recent patch. I now find that AI controlled AH6/MH6 in particular (all A3 helis are affected but to a lesser extent) when told to fly low over trees or over mountainous / undulating terrain will continuously and significantly (+/- >300%) change their flyinheight irrespective of the height set and underlying terrain/tree height and will ignore global and wp speed limits set via: setvelocity and setVariable /while loop. This also seems to occur when just using wp speed settings like - limited etc. Seems they are now paranoid about trees in particular. Whilst the positive side effect of this paranoia is that don't hit anything - the major downside is that they yo-yo over terrain at a proportionately very high altitude. This makes stealthy insertions via heli almost impossible if AI are controlling the vehicle.
AI controlled helis, waypoint following is also more erratic than it was prior to the latest patch even when the wp completion radius is increased. In some cases the AI pilot will just ignore the waypoints set altogether even with large completion radius and careless/safe and captive true and allowfleeing 0 set. If you change the Littlebird to another heli type this issue is far less prevalent but still erratic and not ideal. It almost seems like the AI are terrified of trees(?) and any obstacle higher than +/- 10m and therefore ignore implicit instructions irrespective of whether their actions put the entire vehicle & crew in harms way - and as a side effect creates a yo-yo flightpath effect. We may need to supply sick bags soon to anyone riding in a heli. ;) It also could relate to the AI 'look ahead' distance being too great? Or maybe it's a difference in ASL/ATL? I'm not sure. As mentioned this is far more noticeable since the latest patch.