I can hear the collective groan when my name shows up on this forum already.
In the 100.5 Runtime SDK release notes:
- BUG-000108264 RelationshipInfo is not returned properly from a mobile map package
Unfortunately, I'm not seeing the results of this.

I created a new MMPK after this relate was created. When you debug in runtime:


As always, your assistance and guidance is greatly appreciated. Let me know if you need a repro project, I can provide that relatively quickly.
Details:
ArcGIS Pro 2.3.3
Esri.ArcGISRuntime 100.5.0
Esri.ArcGISRuntime.WPF 100.5.0
Visual Studio 2017
Thanks!
Kyle