The other collection pages are fine. The settings are the same and products do match the conditions required. I cleared the collection cache and that didn't resolve the issue, so I actually rebuilt the collection: https://fringe-co.com/collections/t-shirt
However, the rebuilt collection does not display the items either. This client does use the app Product Filter & Search, which we only use for the T-shirts Collection, so there's a chance the app is the issue, but it's worked in the past (for about a year). The Standard filter trees are working however. When I turn off the Custom filter tree (for the T-shirts Collection) that doesn't fix the blank collection page issue.
It's only the T-shirts Collection page that is blank in the product loading/display section. The sidebar still loads, with the thumb.
Anyone have a similar issue? You see the products flash for a split second before it goes blank.
I just debugged your code and I see that there is an app with the name of bc-sf-filter that is making your collection disappear. It's probably an app to filter your collections.
Either uninstall it or contact their support to have your issue fixed.
This is a quite specific issue, I would not suggest copy/pasting that code into your website since there is not an "one size fits all" solution for this.
Share your URL, storefront password (if it has one) and page with issue, I'll take a look.