Will of the Valk’nir buff prevents you from mounting.

When you receive the Will of the Valk’nir buff from a gem proc you are unable to mount when you are in that form. It completely prevents you from mounting. If you are not meant to mount while that buff is active then the better solution would be for mounting to automatically cancel the buff. Nothing worse than the buff proccing on the last hit of a fight and you’re stuck running around for 30 seconds or having to manually click off the buff.