@BIS Good day!
I remember a time when this problem didn't exist before in Arma3. However, in some update (5-3 years ago) it was added in one patch. This most likely happened when driving from the position of the commander was added, since the driver does it. I'm sorry if this ticket seems long to you, but otherwise I just can't explain this problem.
On the Bohemia website, in the Community WIKI, in the description of the LOAD waypoint it is written:
"The group will move to the waypoint (spatial or object), then any soldiers on foot will board any vehicles the group possesses. They will get into the vehicles as cargo where possible, then as the crew of the vehicle"
No other conditions!
Yes, this is how it worked before, until there was an additional condition for the group to actually load into the player`s vehicle.
The vehicle into which the squad is loaded, must be in the "in formation" status with its commander. If it is not in formation, i.e. the player pressed one the buttons - W/A/D/S i.e. moves on its own, then the AI will not enter his vehicle. Never!! For this reason the problem will only affect the player's vehicle not AI vehicles, because AI subordinate vehicle always located in auto-formation with its commander.
For a better understanding, this circuit is shown here:
If the player is under AI command but this player still the commander of their tank.
After joining an infantry group, the AI-commander of this whole group will have to load into any empty spaces in the tanks (including the player's tank). But if the player drives his own tank, without staying in an auto-formation, then the joining infantry group will never get into player`s vehicle, despite the order of the commander -> Here is problem!
After the commander orders to all infantrymens to get into the vehicles, some of the soldiers will run to the player's tank and will stop in front of it. They simply won't be able to enter the any vehicle, until the player tells their driver to return to formation (menu button - `/1/Return to Formation)
Please fis this problem! Prior to this bug, an AI team was able to load into any vehicle, as soon as the vehicle stop, regardless of whether the driver of the vehicle was in the formation or not. This creates problems. The player's vehicle may be out of formation with the its ai-commander and far away from him, while joined subordinate foot soldiers can be near the player's vehicle. The player simply cannot return to the formation, having traveled dozen of kilometers, and then wait until the infantry reaches him and is loaded into the player’s transport