You could consider moving the aggregator rule above the referring domains rule to give it priority over the referring domains rule - this way there would be no need for the exclusion on the referring domains rule.
It's probably better practice to do it this way round and may make it more simple to trouble shoot the issue e.g. if it you are not getting aggregator traffic you know it is because either the query string parameter is missing or does not contain the value you are looking for.
A couple of general points to note about using query string parameters in Adobe:
- Query string parameters derived directly from the URL are not available on link tracking calls (i.e. only available on page views)
- Sometimes adobe truncates variables so things can get lost if they are part of a very long URL/query string parameter. I think things get cut off at 255 characters during Adobe's processing of the data but I haven't tested this is a while so can't be certain this is still the case.