working on a script to clean-up "individual posts with multiple likes from a user."
"Purge redundant POST LIKES by same USER_ID"
This will be run with the forum upgrader, and can by run through the control panel Content Rebuilder on demand.
It is recommended to also run the "Rebuild Like Counts" Content Rebuilder action after running the purge, which will fix the LIKE counters. Depending on your community, you may need to inform them that their LIKE counter will be updated to reflect accurate likes, rather than the redundant bugged likes, if any.