I've tried removing and re-pairing the device, rebooting the phone and the 735XT. Nothing works.
Please fix! This update is borked.
Yup, I had the same issue with my Fenix 3. Tried re-pairing successfully but it disconnects immediately. So didn't work.
Thanks to AnTiLoop, roll back to version 3.20.3. For those who are looking to get the older version, you can download from apkmirror.com.
Garmin, please release the fix quickly.