Duplicate ObjectID values can be mistakenly created in branch versioned data with ArcGIS Enterprise 10.6, 10.6.1 and 10.7. When this issue is encountered, features with duplicate ObjectID values can disappear when viewing the layer, depending on the order in which they are inserted.
The issue is a result of how the geodatabase returns ranges of ObjectID values when an ArcGIS Pro client disconnects (exits) from a feature service. ArcGIS Pro obtains a range of ObjectID values from a feature service published with branch versioned feature classes. This range of values is obtained the first time a feature is inserted. Any ObjectID values which are not used by ArcGIS Pro are returned to the feature service when the ArcGIS Pro session disconnects.
There are certain scenarios where the ObjectIDs used within a session are returned to the feature service on exiting ArcGIS Pro. The returned values are later reused in a new ArcGIS Pro session. This results in new features sharing the same ObjectIDs with existing features. These existing features are no longer active in the branch versioned feature class and therefore do not display in the map.
The ArcGIS Server Branch Versioning Duplicate ObjectIDs patches for versions 10.6, 10.6.1 and 10.7 have been released to prevent duplicate ObjectIDs from being created. Please follow instructions from the ArcGIS Server Branch Versioning Duplicate ObjectIDs patch page for installation.
Esri has also released SQL scripts for certain geodatabase platforms to detect any existing duplicate ObjectIDs. The output of the SQL script reports whether the branch versioned data contains duplicate ObjectIDs. Please contact Esri Technical Support if the output reports duplicate ObjectIDs, or for any additional questions about this issue.