Same thing on my 645m
EPO=current
Version=7.0 (e036468)
Have had this issue for about 2years. 3-5min to get a GPS signal.
Garmin support told me to sync my watch via Garmin Express on my PC, instead of Garmin Connect on my phone.
1. why would that be different?
2. Can I somehow check the detailed content of the EPO data from my phone?
Mine does something completely opposite. It will alert that the GPS ready when I walk out the door. If I start my run like that, it is a good 100ft+ off the road (eventually it catches up and my track is fine). So despite it being "ready", I wait a minute then start my activity.