It doesn't seem to work for me, I'm using Brave on Android. Other sites protected by Anubis (such as the official Anubis website) work fine.
Here is what I see:
Pressing Try Again does nothing at all.
Edit: by manually navigating back to openwrt.org I was able to trigger the challenge again, and this time it passed. Though it is much slower than on other sites, taking maybe 10 seconds instead of the 2-3 seconds on other sites.