As requested:
Today, on one occasion, I noticed my GPSMAP 66 v340 was not connecting with Garmin Connect 4.23.1 until after I opened the Garmin Connect application on my Galaxy S8 Active (9.0)
On another occasion, I noticed the GPSMAP 66 indicated "Connecting..." (no active Bluetooth connection) - yet Garmin Connect showed the GPSMAP 66 was connected and even allowed me to perform a sync of the device!
I am also still seeing frequently when the Devices tab is opened, just a blank screen with the eternally swirling circle..... Sometimes just exiting and re-opening that tab (not the app) corrects the issue.
GC Logs, screenshots and videos emailed to multiple Garmin Personel.