Do you have an evidence, that it didn’t continue to delete other folders?
I also think that corrupted piece may appear in the trash folder itself, not only in a blobs
folder.
It should. But probably it has a bug:
It should update the usage when it’s finished the batch deletion and flushed to the database after 1 hour by default. However, if there was an interruption in the middle of the process, I think the progress could be lost and you would have a discrepancy there, which should be fixed by the used-space-filewalker enabled on startup. For your system I would recommend to never disable the scan on startup, because seems your setup is unstable.