My QREC, QPL and other recording setup settings stay intact after clearing the track-assigned flex slot. Similar to your experience, the part overlay does not light up to indicate a change. By extension, you can’t reload the part to revert the slot clearing. I suspect this has to do with the slot list being project-wide, thus discrete from the part settings.
Maybe try a slot in another project and see if the settings wipe is reproduced?
I’m on 1.25C.
Anyone else?