Info Box loses focus by itself when attempting to add keyword to a photo

This is a persistent, annoying bug that has been going on for years.

Highlight any photo in my library and bring up the info box. Click the keyword section and you see a blinking cursor where you can type. But in my case, that cursor keeps disappearing after 1 second, making it impossible to type anything. Is it possible Photos is doing something else causing the info box to lose focus, like possibly indexing in the background. I have over 500K photos and sometimes I can add keywords without an issue and other times I can’t do it all day long.