It's not a bug. It's simply not possible for there to be a bug in this.

Does this happen with pvp or npc only?

Your browsers are accessing the page multiple times, it seems.
The next time it happens, check your exp to see if you've actually gained some. If you have, you DID attack, but your browser is clicking the link more than once.

The thing is, it didn't happen to just me...
It happened to me, Arum Exo, bonerinsweatpants, and a few other people that i can't remember.
I deleted my browsers cache, and it still didn't work.
And i wasn't getting any experience.
The Same NPC would still be alive.

I was referring to the fact that CK thought I was bs'ing when I told him this same exact thing happened with me.

And it occurred with both PvP and PvE. I couldn't attack anything for 10 minutes and I didn't gain any experience. I even used a different browser and it still didn't work.

I never said that I just said it definitely wasn't the code.

I have a suspicion that the system clock is losing time. Presumably, if it slips back a few minutes, you'll have to wait until the time pa**es last_attack_timestamp + 3 second.

Wouldn't you think a modern computer could keep the time accurate to within a few seconds! This one is losing minutes.

I'm having the same glitch right now 

hmmm.... its still happening. it just happened to me for the first time. its back 8 minutes from my computer time.