If it indeed is a 'Lock' (as one would understanding a PC locking up), my prior reply would still be the one I can offer:
MP is a very stable product (it has to be for the places where it is used). I would suspect that there is a 3rd party app (likely and AV product) that is a culprit. While not always easily testable in your environment type, a clean-boot would be telling and expose any 3rd party app:
Because it only happens when moving the mouse from one computer to another then the mouse disappears from the screen.
Its just a matter of it disappearing, meaning, you can't see the cursor but you can see the reaction to an invisible cursor hovering over items, and it reacting to that, that's different.
Can you confirm which it is?
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