Web Filter malfunctioning

Hello.

I'm trying to diagnose why certain users are able to browse sites they shouldn't be able according to the Web Filter, so I've set up a test computer and I'm getting weird results.

One of the "must be blocked" sites can be browsed despite checking and re-checking that it shouldn't be available for that profile. I've even made a Web Filter "everything is blocked" however it's still accessible. I'm checking the log, and it even logs as blocked, but I can access it no matter I'm clearing-and-re-clearing cache, using Incognito, different browsers, etc:

Any idea about what can be happening here, please?