[Bug] Able to vote multiple times

Maybe this is intended, but I believe I've found a bug with the upvote system.

http://community.na.leagueoflegends.com/c/beta-feedback/E7c9ol4h-roleplaying-on-the-community-beta

I saw this thread and posted an idea for an improvement.
I was selfish, and wanted my reply to appear closer to the top.
So I up-voted the parent to make it more important.

The thread was moved up, but not to the top of the list.
I proceeded to upvote a separate response to the parent (neither mine nor the parent).

The thread was moved to the very top, as the whole thread seemed more valuable now then the old "best thread" (Sorted by Best)

Testing the theory, I removed one, then both of my upvotes. The thread moved back to it's median and first resting place. Upvoting both left the thread as best, where it currently sits (as of this writing)

Basically, the more posts a main thread has, the more times it is able to be upvoted. So three people with three responses get to vote 9 times for their thread, whereas a single thread with a single response needs to be voted on by more total people to match. I'm assuming your algorithm isn't simply 1:1, but if it is, then it would take 10 people to vote solely for a main thread to beat 3 people voting for a main thread and two replies.

Potential solution: A person's contribution to a thread only counts the highest leveled upvote in a thread. Multiple upvotes in a single thread by a single person are discounted for the purpose of determining "Best"