When I use XPath on and XML result and extract all occurrences, I get a _matchNR = 0 when none are found. But when do the same for a JSON result with JSONPath, I do NOT get a _matchNr when none are found.
The _matchNr is set to 0 when the XPath or JSONPath match but the regular expression after (made with "Starting with" and "Ending with") does not match. So your case, the XPath match but the JSONPath doesn't match, that 's why you get the _matchNR = 0 only for the XPath variable.