e.Site contains an XPathNavigator to the current node. It is worth noting that this is actually different to the xpath that e.Match refers to.
It seems that if you have a repeating group in the xml and then the event is on a field within the repeating group; at this point in proceedings the value of e.Match is such that it contains the xpath to the appropriate field but not the correct instance of that field within the repeating group, as such this means that if you use e.Match to access the field or any fields at the same level it will actually refer to the first instance in the repeating group no matter which instance it really is.

 

Therefore, you must use e.Site instead, in fact I recommend never using e.Match as there is no need for it.