That's the whole point of my (made it on my other account) post- it's SUPPOSED to trigger whenever it procs, not wait for another stun to pass. That's how it worked on retail.
The ability is already skillless enough as it is- you want it to conveniently wait until another stun passes before proccing as well? If it's waiting for stuns to pass to proc, then that's a bug.
Incidentally, the paralytic poison stun only DRs from itself, not other stuns like cheap shot and kidney. Unfortunately, that's part of the ability as designed in MoP, so I can't argue that's a bug. Waiting for other stuns to pass is a bug, however.