Since a couple weeks ago, whenever I try to rep a post by certain people I am given a notice that says that I cannot because I’m doing it too quickly… even if that’s the first and only time I tried to give reputation to anyone that day! I get the same message with the same people, while I am allowed to rep most other users with no problem.
For me sometimes the forum lags and I have to wait a bit before the click goes through. If I don’t wait and click again it says “too quickly”.
BUMP. I keep experiencing this problem. As I said, it only happens with certain people. Is it that you can only give so much reputation to someone before you are prevented from doing it ever again?
It’s sad, it happens with me trying to give one of my Alliance mates Rep as well as certain others… but ONLY them? 
I have this issue sometimes too. Sometimes I even have to refresh the page first. There are also times I am logged out from the forum, while viewing them, and have to log back in.