This is happening to me too past few days for local news programs (running PMS Version 1.32.0.6918 on Windows). The “delete the recording folders” trick worked! I removed the folders, then re-scanned my recorded tv category in plex and the recordings suddenly showed up in the DVR Schedule tab in LiveTV!
I wonder if this is also related to this other ongoing wrong date issue: Date Wrong on DVR Recordings
I hope plex addresses and corrects this problem!