Hello. Thank you for the report.
This could mean that the SAV file has some corruption in it. Extension record 22 defines missing values for long string variables (longer than 8 bytes). If there's an error in this record, then those missing values would be wrong. It could also mean that the file is OK but PSPP can't read it properly because it doesn't understand this particular record properly.
If you're able to send me this file, I can distinguish these cases for you and, if PSPP has a bug, I will fix it. I will not share your file with anyone.