Thank you for writing to us.
Currently, we are working on the major release which should include new updates for the filtering functionality. The case described by you is an interesting one. We are going to forward it to the dev team which works on the major release.
We will keep you updated on this case.
We are glad to inform that the major 2.7 version has already been released and you are welcome to try it.
As for the negation case, we have run the investigation on our side. The existing architecture is not compatible with the suggested behavior. The negation filter is not applied when there are no members.
In such circumstances, we want to suggest a workaround. You can still achieve the desired behavior by applying additional setFilter() API call after the updateData() was performed. That should guarantee that the filtering is performed correctly.
Please let us know in case of any other question.