Storj node suddenly overfilled

[Alexey]

Disk usage discrepancy?

No. They will affect each other and you will have even higher discrepancy, but now because of concurrency of multiple nodes for the single resource - your disk. The fix likely would be implemented before you fill 22TB.

Debugging space usage discrepancies

You may check this: docker logs storagenode 2>&1 | grep walk | grep -iE "failed|error"

If you redirected logs to the file, then you need to search in that file.