So this only seems to happen when you use a closure inside of a function/method call. I made a GIF of it happening just to maybe give a little more insight:
https://imgur.com/ZUsDXaq
The method doesn't do anything special, it's just that it pulls in the phpDoc for the surrounding method and it hangs there until you click away from the closure body. Then if you go back in, you can type maybe one thing before it appears again and you have to click away again to get it to disappear.
Again, not a huge issue, but it's been happening probably for a couple years now and I should've said something a while ago. 😅