I just re-paired my own Shelly1 without much issues which is also on the latest firmware. I did need to start the pairing wizard a couple of times before Homey was able to discover my Shelly1 but other than that there was nothing special. The last couple of app updates did not touch the pairing process so I think it’s something in your configuration.
If you have the skills you could run the app from the command line and pair it from the developer tools. Any errors would show up in the command line console or browser console.
