That's odd and shouldn't be happening. I've literally never heard of this happening before.
Next time it happens, can you please send us your player.log to
[email protected]?You can find it here:
Windows: C:\Users[YourUserNameHere]\AppData\LocalLow\Midjiwan\Polytopia\Player.log
Mac: /Users/[your user name]/Library/Logs/Midjiwan/Polytopia/Player.log
Linux: ~/.config/unity3d/Midjiwan/Polytopia/Player.log