I have to add some information on this topic.
Lately I decided to run decrypt all with the intention to deactivate server side encryption on local disk space. However to avoid users interfering with the process I set maintenance mode to on.
The decrypt all command started without asking for a password and ran through my files but suddenly stopped in between saying everything should be defrypted (which obviously was not, duh!).
Disabling maintenance mode revealed a 503 error on all my files in the cloud so I had to restore the data directory and a MySQL DB backup for the whole cloud. A real pain in the ass.
So, either because of maintenance mode disables the necessary decryption module or decryption function has a bug, this should be really fixed in both ways. Users should be able to roll back encryption once a set of files are uploaded.