Keep losing cursor control

Hi there.
My cursor goes dead every now an again. This means I cannot position it as required. Editing, copying and pasting become impossible. …
The problem seems to be associated with looping code. After typing aor editing something, it goes into a spasm and the cursor freezes. If I save, the problem sometimes goes away, but generally seems to shorten its dead-response time.
I’ve tried switching the formatting marks on and off (in View), and toggling Direct cursor mode (in Edit). But those seem to have no effect. …
Can you help? …
I use Linux Fedora v32. I keep it up to date. (Version: 6.4.3.2 Build ID: 6.4.3.2-1.fc32) … Thanks, Graham

I also have this problem. I have tried escaping, saving my work, not logging off leave in suspended state, logging out and nothing works. Any help would be appreciated