This is reverse-chronological, so needed clues (before retrying) need you to scroll screen down.
You can possibly get a more compact historical view of history at <job> → Show log → Remote.
Seeing it do two dblock Get make me think this might be compact, but need some more context.
At least you now know a name of one broken file. You can (if you like) download it for inspection.
AES Crypt is a GUI tool you can use to try to decrypt it, or you can use CLI SharpAESCrypt.exe.
If it’s compact, that’s only occasional.
You can try. It might do the same thing on the same file. Or you could backup with no-auto-compact.
If that works, then some older file is damaged, but the random sampling hadn’t noticed the issue yet.
Can you easily find the date on the file that wouldn’t download, e.g. from whatever tools pCloud has?