Keyboard intermittently locks up in FrameMaker but still works in all other programs.

FrameMaker 2019 / Windows 10: During an otherwise successful session of creating/editing files, all keyboard functions become inoperative. This occurs approximately once every two weeks of daily use. When it happens, the mouse and menus continue to function properly in FrameMaker. The keyboard continues to work properly in software programs other than FrameMaker. I have tried opening a different FrameMaker file, restarting FrameMaker, rebooting the computer, switching in a known good keyboard, etc. The only thing I have done that restores keyboard function is to uninstall/reinstall FrameMaker. Has anyone experienced this type of problem?