The REPEATINGINDEX holds the index of the List. If you traverse and look at the immediate parent element, it will be a List structure.
For Example, If you take two operators A and B. If A has 2 Access group and B has 1 access group.
Open the XML window, Look for the Accessgroup list element, For A, it contains 3 child elements and For B, it will contain 1 child element. Each ROW child element will have a REPEATINGINDEX attribute.
All the Values in the rule form will be available in the XML. REPEATINGIndex attribute will have multiple occurrences in the XML. (Eg: For Team, WorkQueue) So, there might be some difference in configuration between those 2 operators which you have checked. Check on the immediate parent List. you may get some idea for it.