How do I restart a Remote IMAP session for a user when the logs show "An IMAP retrieval session is already running" for this user?

I have a customer that attempted to setup Remote IMAP. When the results were not immediately apparent they deleted it and reset it up again. They did this multiple times, ultimately resulting in multiple duplicate messages that turned a remote 230MB IMAP folder into 15GB locally. We deleted their Remote IMAP folders and setup Remote IMAP for them again but now the logs show:

[2019.11.06] 09:16:31.699 Starting processing for impatientuser@mydomain.com
[2019.11.06] 09:16:31.699 An IMAP retrieval session is already running for impatientuser@mydomain.com

We deleted any temp sessions for this user that we could find in the \SmarterMail\IMAPRetrieval\ directory, deleted the imap_folders.xml from their \SmarterMail\Domains\mydomain.com\Users\impatientuser\ folder and restarted the IMAP Retrieval service, but the issue still remains.

How do I restart a Remote IMAP session for this user? Is there a cache that I am missing?