@VectorStyler An update:
I lost the tooltips again and this time I was able to resolve the issue more precisely.
I immediately tried changing the Windows Display Scale to 100%, and then back to 150% percent, but that was not the configuration that fixed it.
Under Windows > System > Display > Multiple Displays > Make this my main display.
To start, with the main display was the upper 4K monitor. Changing "Make this my main display" to the lower 2560 x 1440 monitor, then back to the 4k Monitor fixed the issue.
Thank you for your patience, as I must have also tried this when I initially reported this issue, but did not realize it actually solved the missing tooltip problem.