Super annoying. Just about when you posted this, I went to Twitch to get my daily ARP. Everything was working as normal, then I read your post and I double-checked. Did not have any problem. Nothing unusual at all.
Just then, my POS computer froze and restarted. When it finished rebooting and I went back to Twitch, it looked exactly like yours. I only managed to get 1 ARP before it screwed up. Changing the language does not work. Nothing works. It's just not possible for me to get the Twitch ARP anymore.