this?

Just a silly thought, I guess we all use DMS, DMS has an option to freeze AI when players aren't nearby, could it be that thing somehow affecting players?

If you want to test that theory, in fn_FreezeToggle.sqf in DMS, change the section:

if (_freeze) then
{
    {
        _x enableSimulationGlobal false;
        (vehicle _x) enableSimulationGlobal false;
    } forEach (units _group);
    _group setVariable ["DMS_isGroupFrozen",true];
    DMS_FrozenAIGroups pushBack _group;
}
to this:

_i = 0;
if (_freeze) then
{
	{
		if (!(isPlayer _x)) then {
			_x enableSimulationGlobal false;
			(vehicle _x) enableSimulationGlobal false;
			_i = _i + 1;
		};
	} forEach (units _group);
	if (_i > 0 then {
		_group setVariable ["DMS_isGroupFrozen",true];
		DMS_FrozenAIGroups pushBack _group;
	} else {
		_group setVariable ["DMS_isGroupFrozen",false];
	};
}