It seems to me that this is tied to a specific model. A standard helicopter cannot do anything, it cannot even fly normally on points and turn. Apparently, he can only fly straight and land the player's squad and just take off and fly out of the map through the map.
No. The game works fine. Try to make a standard map without mods. Deliver a standard helicopter from the island of thunder and destroy it with the M136. In the file with the log there will be text that this file is not. I have never made such files in max for technology and I do not know what is in them and how it is written. There, apparently, some name of a part of the model is written, for example, for t80 <n><ian><turret> t80u<pid>.
This name can be found in the model file.
i find only.
I'm curious, does it make it crash?
I opened the .anm file with a hex editor and it is very short. Maybe it is unfinished.
It does contain <n><ian>helo<pid>
Maybe other files from HX5 are needed? https://drive.google.com/file/d/1Y4QNYNkrr4FeYeXPp8JlFUBeYKbKlkwB/view?usp=sharing