Glad I have come across this thread! I too am experiencing the same issues but appears in wfHoover, wfNet404s and wfVulnScanners tables using the latest version of WordPress and Wordfence.
Only detected the issue on a handful of sites running on the same server so if it were a mysql bug going on I would be expecting it to affect everything?
Have tried deactivating and activating with no luck…
Any other ideas would be greatly appreciated!