HR abruptly stopped syncing on its own; steps sync, HR during activity saved and sync

(Mods please move if this matches existing issue thread. I did not see one.)

fēnix 5s. Working very well so far. No issues with connectivity, etc. It's way more watch than my athleticism warrants, but I enjoy the data.

Today, at 11:16 a.m. EDT, it stopped sending real time HR to GC.

I can see my HR on the display, in live #s.

Steps continue to sync.

There is no scale on the last 4 hours display, though, and that graph appears to be the 4 hours ending 11:16.

When I rebooted the watch the only thing that did was wipe out the last 4 hours HR display.

When I went for a run about 3:30, watch connected no problem with the HR band and the entire run activity including the HR uploaded to GC.

The HR display in GC has a graph from midnight to now, showing HR to 11:16, a little "run" pictogram where the run was on the timeline, but no HR since 11:16.

(Maybe I died and this is the afterlife...)

Is it just me?

(UPDATED: at some point in the last hour, it decided to upload the missing timeframe **but** the graph is patently inaccurate. The "high" HR is a good 70bpm lower than the high during the run. Previous runs showed accurately on the HR graph (with colours for HR zone). So, status changed but still not correct.)