This is still an ongoing problem and makes the software look really amateurish.
It's been a long term issue with no apparent attempt by Garmin to fix it.
Very unimpressive.
Since this is the Garmin Express Windows forum, I just want to make sure you're talking about Garmin Express for Windows and not the Garmin Connect Mobile app. If it's GC Mobile for iOS, the issue is currently being discussed here: Every time I restart my phone I have to Login In and Reconnect Devices