Did you ever figure out what was causing this? We have also been experiencing sync error with "no details".
Mix of iphones and Android tablets, using both data connections & wi-fi.
Most of the time (4/5 times?) the data has actually synced, but the off one has not and has had to be backed up from th e device.
- for iphone users they get the error, but in the background the # of edits to be synced re-sets to none
- for Android users, the # never re-sets and still shows that the edits are waiting to be synced.
Field crews are definitely getting frustrated, and they're losing lots of time while we verify that the edits have actually gone through before they can change to a new work area.