Highlighted words in Find/Replace are showing on screen in all apps

Hi, I'm running MS Office 2019 version 16.3 (19101301) Desktop version on a 2024 Mac Mini with Tahoe 26.2 OS. I just bought this Mac Mini in the last week. Previous to that, I had a 2020 MacBook Pro running the same MS Office version with Sequoia 15.7.3. I never had this issue on the MacBook Pro; it has only started on the Mac Mini, so I'm wondering if it's an issue with the Tahoe OS.

So here's the issue. When I do Find/Replace in Word, all the words I'm searching for are highlighted. Once I replace those words, the highlighted words still show on the screen, but not where they originally were in the document. They are floating artifacts on the screen, and they remain in the same position on the screen in every other app that I've got open. I've attached a number of screenshots showing the Word doc, the starting page for this forum, the DuckDuckGo landing page, and the Apple Clock.

The only way I can get rid of these floating artifacts is by closing down Word altogether. Just closing the document I was working on doesn't fix it. It happens every time I do a find/replace in any Word document, not just in one.

Any suggestions? I'm not interested in subscribing to Office 365, but I'm wondering if my version of Office is old enough that it needs to be replaced (MS no longer supports or updates it). Maybe it doesn't play nice with newer Apple OSs? I'm a technical editor so I use the Find/Replace function all the time; I can't shut down and restart Word after every time I do a Find/Replace. This is more than a little frustrating. 

Thanks!