Watch face weather showing “- -“ even when iPhone nearby

Fenix 6 pro, using a garmin watch face. Have weather as a data field which works, but after a while the temperature reads “- -“ while what I think is the rain indicator has a %. 

If I manually sync my garmin connect on my iPhone it updates, but even with my phone sitting next to it, it eventually reverts to the “- -“ again.

Any ideas? Maybe it’s a garmin connect thing. I don’t recall my vivoactive 3 ever being greyed out in GC and needing manual refresh / sync like this. Any controls I need to check?