Thanks Luis, that was just an open-ended timerange hack.
Here’s a version of the page, that has zero script on it, except finsweet’s filtering.
https://cms-filter-test-da71c9.webflow.io/basic
Here’s a capture of exactly the same problem occurring on an android device ( also seen on some chrome desktops as well as an iPhone / Safari ).
On these devices no errors are reported but filtering fails on a closed date range.