We have 3 people working in the field (using separate iPads and separate log-ins) who are getting sync errors when trying to upload their map edits. They are working offline and only trying to sync with a strong internet connection. No schema changes have been made and nobody has touched the layers except within collector to add points/lines. This is not the first time and in the past we have had to publish new maps with the same layers in order for syncs to occur without errors. The people in the field are also unable to see any edits made by other people when they could in the past. On a computer in the office is the only place where all (synced) edits by different user names can be seen.
Why is this happening? Why does this keep happening? We are not changing anything mid-project and are following all known workflows for using Collector.