Here is an example where the same QuickStatements batch has added the same statement multiple times. I have seen similar behaviour occasionally before but that had only involved duplicates, and I dealt with them as part of normal duplicate cleanups and did not dig any further. This example, however, indicates that there is a need to dig a bit deeper, hence this ticket.

The QuickStatements formatting came from the Author Disambiguator, but I suspect the issue is on the QuickStatements end.