The MS Word context menu does not always work. How to fix?

Question

Microsoft Office

The organization uses office 365. It was noticed that if you select text in word and call the context menu by right-clicking, sometimes the menu does not appear, but instead the selection is reset, as if the left mouse button is triggered.
The behavior manifests itself on different machines, so I exclude the problem with the mouse. Also, one of the users claims to have seen this behavior in earlier versions of Office.