I have pinged a group only once and even left my thread topic to make sure it doesn't get refreshed by accident but when my ping goes through it sends out 3-4 pings each time...This happened to me for two seperate groups that i pinged today.
I would reccommend editing out the ping as soon as you post it. I know the multipings thing is supposed to be fixed but apparently it's not, but that worked for me before the most recent "fix." The only problem is that there's now a delay before the ping actually goes through so you don't know for sure until it sends 15 times