I am having trouble getting a feature service to sync after downloading for offline use in Collector. I am running Collector 10.4 on Android (fails on iOS device as well) with feature services published to AGOL from a file geodatabase. I have several point features and line features that work great in a connected AGOL editing environment but only the points work when I take offline. All of the points sync back and no errors occur. If I try to sync edits to this one line feature service I get a sync failed error:
"An error occurred while synchronizing edits"
Note: I've taken the data out of SDE to eliminate any M value issues, versioning support for offline editing, etc. so this file geodatabase test is as simple as I can make it.
Any help is greatly appreciated.