Filter by tags bringing back articles that do not match the tag

Hi there,

I have started to use the product to present data using selection by tag. I have selected a tag that has 6 articles. Those are presented on the page (correctly), but so are a whole bunch of articles that do not have that tag:

welshfencing.me/selection-articles/cadet-winton-2025-selection

How do I exclude articles that do not have the tag? Is this actually a fault, as selection by Category works just fine.

Regards,
Mark