I recently came across the same problem (with PR 1.3).

I also solved it by clearing the browser history, through Settings/Web/Clear Private Data. I first tried clearing only the Browsing history and rebooting, but the problem remained; after selecting all options (Browsing history, Cookies and Passwords) and rebooting, the problem went away.

I since tried to use Bill Pay again, and the problem reappeared, so I'm assuming that it doesn't work with my carrier anymore (O2 Ireland). CCard payment still works fine.