Hey guys! I'm having a similar issue with my thinkpad T460s. The keyboard letters f, j, k, l, and backslash (\) all don't respond, while every other key works just fine. I purchased the laptop used, so wasn't expecting everything to fully work.
Since the keys are mostly all in the same row, I was wondering if it was a dirty contact on the connection, or if something was trapped under the rubber layer. I still have yet to fully disassemble the keyboard (check under the rubber contacts/use contact cleaner), but after taking out the keyboard and cleaning it extensively there still is no fix for the issue.
Does anyone happen to know the layout of the ribbon cable that thinkpads use? I'm wondering what contact is the one responsible for the a-l row, and if that could be the cause of my laptop's issues.