Can't Access Shared Multimedia Folder on separate volume after Firmware Update

[rabidpossum]

I have two volumes on my NAS; one for programs and backups, the other one is for media, where I have my shared multimedia folder that I use to store all of my Plex media. After the most recent firmware update, I can't access the multimedia folder anymore. When I go into the file explorer, the multimedia folder no longer appears on my media volume. It's as if there aren't any folders on that volume anymore (it gives me the option to create a new shared folder on that volume, but my existing folder is completely missing). I know that the data are still there, because in the storage manager, I can see that the volume is still full and my Plex server (installed on the same NAS), can still access all the files in that volume, even though I can't see them. There's also a new Multimedia folder that just showed up on the other (program/backup) volume; it seems like the new firmware somehow "reset" the Multimedia folder and it's making the NAS ignore my old one (I'm just spitballing; I have no idea what I'm talking about in that regard).

Is there any way to recover or regain access to my Multimedia folder?

[rabidpossum]

Quick follow-on: I can SSH into the NAS and see my original Multimedia folder and everything within, but it's not visible from the File Station app.
Any thoughts would be appreciated.