Standard only defines behavior of SQLRowCount for statements generating affected rows number, i.e. for upserts etc. For other queries it says it is driver defined.
If resultset is cached it is possible to return row numbers in it. And for single statement queries connector does that. Thus we have at least inconsistency in connector's behavior.
It's not quite clear if it is ok to fix that in terms of maintenance release, or it can break applications using current versions. There are pros and cons