Bizarre File Export behavior! Won't let me name, rename or select folders right

Strange problem in X8: When exporting a file to PDF, JPG, anything -- the file export box shows up, and I click thru the folders to get to the destination. When I go to type in the filename, the Windows 'halt' chimes go off with each keystroke, and the folder window cycles through the different view states (large icon, detail list, etc).

This happens on all of our PCs (Win7 and 10) running X8. X4 doesn't do this. All other programs (Adobe, Office, etc) do not exhibit this weirdness, either.

It takes three to four tries before we can export out. Also, when creating file folders (in the File Open or File Save As) the same thing happens -- but it gets weirder: typing or backspacing wipes out entire words in the filename, rather than just one letter at a time. Again, this is only happening in X8 and it's driving us NUTS!