Thomas,
I dont see any indication this was ever resolved with Support. As I mentioned before I believe this has to do with editor tracking fields. Can you check the schema of your problematic service? If you have editor tracking on you should only have these 4 fields:
Editor
Creator
EditDate
CreationDate
The names could vary depending on how you added editor tracking, but there should not be any duplicates (ie. Editor_1). Let me know if you see something like this.
Regards,
Colin
Regards,
Colin