Restore issue, "Restore Value is greater than keyspace"

I have a session called "1" that ran for sometime, I aborted it with the "C" checkpoint option and now would like to restore it. I checked the hashcat directory and there is a file called 1.restore, I assume this is the checkpoint file. The following command;

hashcat64 --session=1 --restore gives this error message:

Restore Value is greater than keyspace

Any ideas?

Thanks.