Hi, apologies in advance if this issue has already been identified. I’m using a clean install of version 6.1.6.  I’ve noticed an issue with document types.  I changed the tab name on a document type then added a property to that tab on another document type that inherits from the previous document type.  The affected content nodes look fine and contain the new property, but when I go to edit the document type I added the new property to - I get the error “sequence contains more than one matching element”.  Looking at the database, it appears to duplicate the re-named tab in the cmsPropertyTypeGroup table whenever a new property is added to it.  Deleting this duplicated record seems to fix the issue.