PopUps Don't Load and/or Crash Field Maps

[DavidMurray_ODWC]

I have a working Web Map that feeds a working Experience App.

The project lead wants users to be able to view/use the map via the Field Maps App (initially, it was the Explorer App, but as that is being retired this year...).  But there have been issues.

No matter the phone used (Android/Apple):
The Large Circular symbol in the center of each Trail Loop ~ The PopUp refuses to load.  The app becomes unresponsive (though you can still pan the map around).  Eventually Field Maps will Crash (after somewhere between 15 and 35 minutes of swirling).

On Apple phones:    (Admittedly, a less pressing problem.)

Destination  locations that are not considered "scenic route starting points" ~ "Errors" "Unable to Load All Data"   ...Error Code: 19.  But the 4 custom expressions listed are those that pull related table text fields into the popup for scenic route starting points.

See the Blue squiggle in the Panhandle?  Point 1-7 is a "scenic route starting point," as is 1-6.
Any other Destination (1-#) along the blue line is not a scenic route starting point.

Any advice for resolving the PopUp-Not-Loading issue would be very much appreciated.  

Why does this happen?
Is there a current solution/workaround?
Is there a future solution planned?