This entry from Michael13767 has been informative if for the only reason I've discovered I'm not the only one with this issue.
It definitely occurs in larger documents, as suggested, greater than 100+ words. The cursor is visible at the beginning of the document but then disappears somewhere in the second half. (I jump to the end to test this.) If I click with the mouse, I see the
blinking cursor but as soon as I use the cursor keys to change position, or type something, the blinking cursor disappears.
If I zoom to 3 pages, the cursor remains visible. If I zoom to two pages, it disappears.
Today is November 14, 2020. I think I first noticed this phenomenon about a month or so ago. Maybe two.
A related observation
I have a large document, 200,000 words. When I first open it, I get "Not responding" for 15-20 seconds. If I jump to the end, same thing. After this initial delay, Word seems to find its way and responds quickly. But at that initial opening, Word seems to
get lost and I have to wait through "Not responding". Like Michael13767, I thought of document corruption and copied and pasted with Notepad++ to create a new Word document. That didn't correct the issue. Since the point of this large document is to have a
one stop, archived, searchable repository, I've considered moving to Notepad or WordPad but hate to give up the convenience and features of Word.
I also recreated the Normal template but that didn't correct the issue.