Hi guys,
Similar issue here as well after beta update. MP mission with multiple client planes. Weirdly.....if me and my buddy both choose a10c's, it works fine, as normal. If i went in as the su-25t, and my buddy in a10c, then i can see everything as normal, including him moving his plane, but he cant see me moving.
To test, I talked him into ramming me - collision detection definitely still works!