Firefox

When I Find-in-page for a term using ctrl+f or "find as you type" with "Highlight all" turned on, all results will appear highlighted. But then much of the time several seconds (variable) later it goes away, as though I had hit esc. If I hit ctrl+g for "find again" it starts again at the top. So current place in page is lost.

This happens even if I take my hands away from keyboard/mouse. It is not some kind of input I am doing.

Does this sound framiliar to anyone? Is there a way to make the "find" results stay found?

Or is there an add-on which reliably implements Find?

I have problem on multiple devices, for a long time, and with linux, windows and mac.