and they cannot be deleted either
Sounds like a known issue that's easily fixed by rebuilding one or more index in your file.
For More Information see: Phantom Record, damaged file message, Recover can't detect a problem
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip