Play the Combined Arms showcase with (only) CBA_A3 (v5), Old's Real Armour mod (RAM), and either Taosenai's bullet_value mod or Redfield-77's bullet_value mod.
Both helis behave oddly. In particular, the heli carrying the player does not get a "disembark" order but overflies the OPFOR compound. Sometimes does so repeatedly, but usually crashes somewhere - occasionally having received a "disembark" order.
The other chopper rises to fire at the compound a couple of times then lands, usually displaced to one side or another of the LZ. Frequently crashes when doing so.
To me it is really bizarre that changing a few 'structural' configs should so thoroughly bork the default AI. I have used multiple mods in A2/CO that modify similar config values - alone and in combination - and have never seen anything like this.
See also description in forums, this has the links to the relevant mods: