Originally Posted by Tigerious
x86 or x86_64 ?
English mothafocka, do you speak it?
Windows Vista, 32-bits
And no it's not client dependent, this bug has happened to me before several times and I don't like it.
EDIT: found the bug, it's also the cause for the trouble I had on Raven with a few save campers. Your steps to reproduce are correct, you just missed the most important thing at the beginning: Be afk for 10 minutes.
No joke, I don't know why but if you stand afk for too long you become unable to cast spells and be targeted of spells(For example: resurrection dizziness doesn't work when you respawn at the altar) until you move. Now, if you try to cast a horse while in that weird state, you're unable to switch back from combat stance and vice-versa.