Got 502 Bad Gateway code from NGINX when I wanted to update Tailscale.
Forgot to mention the method of access the device - GLKVM application on Mac.
How are you trying to upgrade tailscale on the device? Can you post screenshots of what you are doing and the error you are getting?
NGINX issue occurred when I clicked Access Terminal being in GLKVM application, for updating Tailscale. Sorry for miscommunication on my part.
I tried it from Chrome and the terminal opened normal, without issues. After that I tried accessing terminal from GLKVM again on another day and it worked too. Hence, it is not reproducible anymore.