I echo this complaint/issue. Garmin support says it is something "they are working on." I had it until yesterday. All the data is there, it just doesn't show the graph.
same here for the last few days ... timeline magically disappeared
this is just a nice-to-have. My personal timeline has o hours to look into this but it would be nice if it worked.
same for me. Data is on the watch but not in the app. No heart rate, intermittent pulse ox basically no data at all in the app since 1st September
Same here three months I’ve had no timeline data displayed/ and prior to that it was perfect