When seven or more photos are opened in the light table, some icons in the menu bars overlay others. I tried to click the bookmark, but got Full Screen instead.
This is on an iMac with the latest PSu version 4366. I don't know how long this has been an issue as I do not often open that many photos in the light table.
I found that unpinning the menu bar makes the icons normal. And they stay normal after re-pinning.