If posts containing tags appear in the Search dropdown list, and the list is long enough that it shows the scrollbar, the tags displayed in the list ‘float,’ overlaying text underneath, and not scrolling with the list:
I see this on Plex’s forums using Firefox, Vivaldi, and Brave browsers on Linux Mint 20.2. Also in Vivaldi, Chrome, and MS Edge (92.0.902.78) on Windows 10.