Error Message when trying to recover files found on SD Card

After running Recuva on "movie" files on a 64gb SD Card I use in my Camera it listed about 37 files.

All but 1 are marked green (dot) and indicate an excellent chance of recovery.

When I try and recover any or of them to my PCs HDD I get the following message against each file; none are recovered.

"The volume for a file has been externally altered so that the opened file is no longer valid".

What does this mean and why does Recuva report (seemingly incorrectly) that I have an excellent chance of recovery for each of these files?

I have no experience of this message. Recuva's state means that no live file is currently using the deleted file's clusters. Recuva can't check the contents, it recovers what is in the clusters irrespective of the content, which may well have been overwritten by a file which is itself now deleted..