I added a filter to match a field, date, and it only matched 4 of the 12 templates that have the same value (December 2021) for the field. I attached images showing how I set up the filter in the set editor, the 4 templates that show up, and then showing the inventory with all 12 that are supposed to show up with that filter.
the 4th image I attached shows November 2021, which matched perfectly and shows all 12.
The 5th image is showing October 2021, and only 10/12 of the templates show up here. This is set up slightly differently, in a different schema with a different filter, this time just matching type (Collect Art). The 6th image shows how I set this filter up.
I tried setting up a few other filters, to match on rarity for example, and some of the templates that were not showing up before when matching for the date, were showing up matching for Epic.