Freron MailMate

I have a mailbox where the "Archive" folder is actually empty because there are yearly folders underneath it. However, the "Archive" folder is still set as "Archive" mailbox type.

I can activate "Include messages in any submailboxes of this mailbox" on the "Archive" folder of that account. It will fill up that folder with the messages from all the subfolders just fine.

However, under "Archive" at the top (under "Mailboxes" the blue mailbox that is kind of like a smart mailbox for special mailbox types, but without the smart mailbox icon or it's settings) that account's subfolder is always empty. Which also means they often get overlooked while searching.

How do I tell MailMate that there are subfolders to the Archive folder and that all of them contain messages that are to be included, not only at the Source level (at the bottom), but also at the Mailbox level (at the top)?

Fun fact: If I activate said option on the "Archive" folder of that account, it also activates on that account's subfolder within the "Archive" mailbox at the top (under "Mailboxes"). When I unchecked it there, however, it does not deactivate for the "Archive" folder of the account at the bottom (under "Sources"). Well, the box is no longer checked, but the messages still display until I enable and then disable the checkbox again.