Windows Explorer was renamed File Explorer in Windows 10. They are the same thing. Microsoft just changed the name after 24 years to make it harder for people to talk about things (and maybe because people kept confusing Internet Explorer and Windows Explorer).
Issues with right-click context menus are almost always caused by third party shell extensions.
If it only happens once every few hours it could be hard to track down, but you could try disabling the installed extensions and then slowly re-enabling a few at a time until the problem returns, until you narrow down which one is causing the problem.