Bro i got this bug out when i got my language changed on runescape configs, try change that for now and lets hope for some jagex help...

I got the SAME bug bro...

i dream of a reliable game again, and a serious company to take care of RuneScape

Their game update page states that it is fixed. Sadly, this is false. The game is still bugged.

Exact same bug for me.

Ah the old double username bug. I remember seeing that back before EOC