I am getting an error that is popping up for a lot of the mail messages:
“The message … could not be moved to the mailbox “Spam” the specified object was not found in the store., The process failed to get the correct properties”
It sounds like maybe the mailbox specified in the drone script doesn’t exist. However, because the error seems to be coming from the server rather than Mail itself, it may be that Mail thinks the mailbox is there but the server doesn’t.
Do you see a top-level Spam mailbox in that account in Mail? Are you able to drag and drop messages into it?
It may also help to just create a new top-level server mailbox called SpamSieve and set the pSpamMailboxName in the script to use that.