Anubis is usually less obtrusive than that, though. This is the longest anubis challenge I've ever had, to the point of being absurd. Hopefully they have a genuine reason for having set the difficulty so high.
It's near instant on desktop (Windows/FF/7950X3D) and I wouldn't expect the delta to be that large against a modern mobile device.
Seems like it. It loaded near instantly as well from my Android smartphone using Firefox.
And contrary to the directions, refreshing the page DOES help.