Varus Q not charging up

I tried Varus out last week when he was free, and couldn't charge up his Q. The tooltip said first cast would start charging and second cast would release it, but it just insta-released for me. I tried holding down the key and I tried pressing it. Either way, insta-release.

My key bindings are not the standard, which is the only thing I can think of that could be the source of the difference. I use dvorak and have a relatively standard binding map, so ',.P is QWER.