At first when I logged in, This Device and my phone appeared. I tried to rename This Device, but it said I could not because I didn't own it. Then it disappeared and only my phone appears. In The Join Android app, it never appeared. Only phone phone appears on the test site as well.
...and of course right after I submitted the issue, This Device appeared again and I was able to rename it. I did choose to "switch accounts" and logged in again, maybe that helped.
At first when I logged in, This Device and my phone appeared. I tried to rename This Device, but it said I could not because I didn't own it. Then it disappeared and only my phone appears. In The Join Android app, it never appeared. Only phone phone appears on the test site as well.
Manjaro GNOME
joindesktop-git
(my AUR package) Node.js 14.5.0 NPM 6.14.6