Hi Tiff - did you get a solution to this? I'm having a similar issue in some apps, when you click on the map and the result(s) is returned to the sidebar information panel, using the zoom to button on the result doesn't zoom to the full extent of the feature.
The issue seems to be if it needs to zoom out, it will zoom in from a wider extent to the feature but won't zoom out from a closer extent to the feature.
Its working in some instant apps I have but not all and I can't see any reason why there should be a difference at the moment, they're all using map services from referenced data from the same federated geodatabase.