Sync Works On Both Clients, Both Ways, but not for existing notes in One Client

Hello,

Android App
Version 1.2.6
Database v34

Desktop
Linux Mint 20
Version 1.2.6

Syncing to self-hosted Nextcloud instance.
This has worked for me in the past, but I just added a new Linux client and all existing notes are not syncing. If I create a file on the desktop, it syncs, and is visible on my phone. If I create a note on my phone and sync, it's visible on my desktop. Works fine. However, existing notes on my phone (and all other clients) are not syncing to my new desktop client. The webdav directory is the same, they use a "joplin" user I've been using in Nextcloud and the root nextcloud directory of that user is used for syncing. I am NOT using the Beta Nextcloud Joplin app.