The hint is what you got in the one-line summary, which omitted the detailed error.
Some problem is showing up with those files, maybe while verifying backend files.
Can you try for a more detailed report from About → Show log → Live → Retry?
The TEST command has more. Did you set up –backup-test-samples or similar?
I’m not sure if the three rather-close-together errors were from one backup or not.
I suppose you could also see if the file still makes sense or if it’s been malformed.
AES Crypt should decrypt it. If you prefer CLI, use Duplicati’s SharpAESCrypt.exe.