Can confirm that this is something we've known for a while. The horizontal and vertical feeds manage data independently. The cache is essentially not getting updated when you vote. But your vote is indeed recorded, in fact if you vote in the horizontal feed first, go back to the vertical feed and then refresh it. You'll find your vote present. Trying to get this one fixed has proved harder than we thought. They say in programming there are only 2 problems. One is naming variables and the other is caching.