This bug was last reported and fixed in #4838 (thanks GitHub new Related Issues feature!) which was released in 4.9.3, and it is back again. Noticed this on dataverse-internal running v. 4.15 build 302-beb88dc, while I was presenting (thanks @scolapasta) the dataset pg UI at the community mtg.

Could be related to the accessibility changes to the buttons in #5717 merged in 4.15, that included changes to the button for popup, as well as other style changes and render logic refactoring.
Sigh.