AppImage not unmounting when running as systemd service

I have an AppImage that when run on the command line, works just fine. Executes as expected and cleans up the mount point on exit. However, when run as a systemd service, regardless if it exists cleanly or with a failure, the mount point is left behind in `/tmp`. This ends up accumulating a bunch of stale fuse mounts and after long enough the mount limit is reached and no more appimages can be run.

Any ideas why running as a systemd service might prevent the mount point from getting cleaned up?