Indeed, thanks for the logs and your patience!
Mar 13 16:19:26 tigger systemd[1]: Stopped Network Manager. Mar 13 16:19:28 tigger systemd[1]: Stopped target Remote File Systems. Mar 13 16:19:28 tigger systemd[1]: Stopping Remote File Systems. Mar 13 16:19:28 tigger systemd[1]: Unmounting /media/test_mount... Mar 13 16:21:34 tigger systemd[1]: Stopped target Network is Online. Mar 13 16:21:34 tigger systemd[1]: Stopping Network is Online.
So we need to fix that in NetworkManager's units, it needs to stop after network-online.target and network.target.
Indeed, thanks for the logs and your patience!
Mar 13 16:19:26 tigger systemd[1]: Stopped Network Manager. test_mount. ..
Mar 13 16:19:28 tigger systemd[1]: Stopped target Remote File Systems.
Mar 13 16:19:28 tigger systemd[1]: Stopping Remote File Systems.
Mar 13 16:19:28 tigger systemd[1]: Unmounting /media/
Mar 13 16:21:34 tigger systemd[1]: Stopped target Network is Online.
Mar 13 16:21:34 tigger systemd[1]: Stopping Network is Online.
So we need to fix that in NetworkManager's units, it needs to stop after network- online. target and network.target.