It's possible you reached the group limit. Once the upper limit of groups active is hit, you can't place anything in zeus.

In T123238#1581813, @Vipera wrote:

In T123238#1581753, @AtomicTim7 wrote:

I'd be intrigued to see, comparatively, how many instances of the bug/crashes you get with the option enabled. You may find there are more, you may not.

There have to be the same stress test for both cases, with virtualization disabled and enabled. If you make different game situations then result is not correct.

In T123238#1581665, @Vipera wrote:

I was going to disable Intel Virtualization in BIOS to see if it helps and have found that I have already this parameter in disabled state. And it was disabled for a long time on my system. It means that this parameter does not help at all with the "3 fps" bug.

In T123238#1578329, @Lex wrote:

Someone can try and check it. I have disconnected BIOS Intel Virtualization Technology, result:

• FPS in a game is stabilized better
• It is less friezes
• The fragmentary sounds characteristic to FPS falling don't appear in a game
• In a game on the server, with MOD, 30 players, about 3 hours a game lasted - hasn't seen a problem 3FPS
  

In T116765#1443755, @Lex wrote:

This issue should be widely disclosed. This applies to all weapons, the whole technique.
Such a mechanism as a "camera stabilizer" - is not implemented in the game, and it's sad.
How it should work today:
https://www.youtube.com/watch?v=Gf1Vm7LQ2vE&feature=youtu.be
https://www.youtube.com/watch?v=T-jQjX8el6Q
https://www.youtube.com/watch?v=pfGP-dGjjnY
The question asked here.
https://forums.bistudio.com/topic/189468-feature-request-correction-of-a-sight-in-heavy-battle-tank/

The problem isn't with any particular drone, and it isn't limited to a game with mods, it occurs in vanilla too.
The problem I think is something to do with remote controlling units, but only in a multiplayer environment.
See video: https://youtu.be/1YtQ9af9pzs
This was recorded solely in vanilla, with cam shake disabled in difficulty settings.