Around mid-August, Garmin Connect would repeatedly lose its connection to my Vivosport with errors "Device Not Connected" and "Your vivosport disconnected from Garmin Connect unexpectedly". I could recover by re-pairing the Vivosport but this was time consuming due to pairing issues and having to customize my Vivosport widgets. Garmin Support had me go through the usual troubleshooting procedures which I had already done. At the time, I was on Garmin Connect 5.4.1 - I initially thought reverting to version 5.3.1 stabilized the connection but later started to see the same issue. After multiple calls to Garmin Support, one of the support agents mentioned an Engineering ticket related to connection issues with Pixel 7-series phones but could not see any details.
I tried multiple ways to recover the connection without re-pairing - the most reliable was rebooting my phone. I started checking the Bluetooth 'paired' list before launching Garmin Connect. Usually, Vivosport showed as 'connected'. Sometimes it showed as 'paired' - this typically meant Garmin Connect would require up to 30 seconds to connect. However, sometimes Vivosport would not show in the paired list, which was related to the "Device Not Connected" issues. I discovered that turning Bluetooth off on the phone, waiting a few seconds, then turning Bluetooth back on would cause Vivosport to reappear in the 'paired' list. Sometimes Garmin Connect would connect but if was already in a "Device Not Connected" state, closing the app from the Android open application list once or twice reconnected the Vivosport.
Without seeing the details of the Engineering ticket, it is not clear if this issue affects Android phones other than the Pixel 7-series or devices in addition to the Vivosport.