Not sure which version you are running but I had just tried it on my 18.104.22.168.202 which is working fine. See below screenshot. Once marked as malicious, it will be added to the "User Blocked Rogue Devices" table.
I tested earlier using Safari - Version 14.0 (16610.2.2.4). Now also tried on Chrome - Version 85.0.4183.102 (Official Build) (64-bit) with the following screenshot working fine too. Maybe some of the Chrome plugins you have. Try the incognito window and see if behaves differently with plugins disabled.