Here is vanilla test without anymod.
Heli is b, truck is a
try following and see the rotors are never stopping if engine was on before the command
b attachTo [a, [0, 0, 3]];

"18:51:59 Warning Message: You cannot play/edit this mission; it is dependent on downloadable content that has been deleted. a3_characters_f

please close this one..
Thanks Wulf. My mistake.

please fix this..

this is not affecting only triggers.
It looks like combo boxes are broken for a specific position, for example Firewill's F-16 mod loadout module has same issue for Hardpoint 2. It is not possible to open that combo box to load a weapon

Still no solution on this issue? It has been already 2 years as far as I see and still Helis cannot detect infantry until they fire at heli