Every other BT device I connect my phone to - headphones, keyboard, car, Edge 1000 - connects instantly and stays connected without problem. With the 1030, when I power it on it usually takes up to ten minutes to establish a connection to the phone - after I start an activity, the two don't usually connect until I've ridden somewhere between two and five kilometres - and I have never managed to get through a ride without seeing multiple instances of "phone disconnected" and then "phone connected" appearing on the 1030 display top line. It make no difference if I start GCM and leave it sitting in the foreground, there is still an extended delay before the connection gets established.
Lest anyone thinks this is indicative of a faulty unit, this is the fourth 1030 I've had, and they all have had the same BT connection problems. Garmin replaced the previous three 1030 units because they all started suffering from the screen delamination / blue halo problem. The problem has also persisted across both the phones I have had since first acquiring a 1030, and across three different versions of Android. Phone is presently a Pixel 4 running Android 10 and GCM 4.31, and 1030 has 9.50 FW, but I've had the problems all the way back to an earlier Pixel 2 phone running Android 8.1 and FW 3.something on the 1030.