Hi Daniel,
You are correct, accessing related records is supported in our current version of Explorer. Currently we support getting related records from the origin feature to the destination feature only. So, for example - you can tap on a Hydrant and get it's inspections, but not the reverse (presuming the relationship set up with Hydrants as the origin and Inspections is the destination)
Is it possible this is what you are running into? And that if you tap the feature in the other layer, you do actually get related info? If this is the case, and you would like to have this additional support - it would be great to hear more about this requirement and your particular workflow so we can understand your use case.
Whether it's this case, or something else we'd like to hear more about it. If you could email Explorer4ArcGIS@esri.com with the details of either scenario that would be great. Then we can get into the details there.
Thanks for the question and the feedback.
Heather
bpierce-esristaff