When I edit a Feature Service (line feature class) directly in ArcMap I go through the following steps:
1.) Create Local Copy for Editing
2.) Start editing, delete hundreds of line features, save edits, and stop editing
3.) Synchronize Local Edits with Server
When I do these steps the following error message appears:

When I go to ArcGIS Server Manager and look at the error message it reports the following:

Has anyone experienced this error? Is this an ArcMap or ArcGIS Server BUG for 10.6.1. We are currently running 10.6.1 for ArcGIS Server, ArcMap, and SDE Database.
FYI - When small edits are done with the same process above, it will sometimes sync back local edits with server successfully, but not always.
Thanks!
Greg