Filter Blocks Not Working as Expected

I have been using your Pofily product filter on my website, kingwoodhobbies.com, for a while now, and it’s been working great. I am trying to create more filter menus, and I’m running into some issues:

The filter block called ‘Find a Deck’ is working flawlessly and is applied to the Product Category ‘Deck Market’.

I have another filter block called ‘Search Destiny Cards’ that is applied to the category ‘Singles (New)’. That product category displays all of its filter blocks correctly, but clicking additional filter replaces the currently chosen filter instead of adding to the selection. For example, if I choose the filter for Era=FFG it sends me to the URL of ‘https://www.kingwoodhobbies.com/product-category/destiny/singles-new/?pofily-tag=ffg’. If I then click on the filter for Color=Gray it sends me to https://www.kingwoodhobbies.com/product-category/destiny/singles-new/?pofily-tag=gray instead of https://www.kingwoodhobbies.com/product-category/destiny/singles-new/?pofily-tag=ffg,gray.

If I remove this filter menu from that category and try to create a new filter menu applied to that category, Singles (New), no filter menus appear on the page.

The filter menu ‘Find a Deck’ is working exactly like I want it to. I would like the rest of my filter menus to work the same way. Can you please tell me what’s wrong?