SBC Enterprise Server Edition ping dropping

I would like to share a behaviour observed at SBC-Server Enterprise Edition running on a HP Proliant server. Our customer told us to use ping to check whether the SBC was alive in their network, which is a non standar procedure to watch it. We answer him to do so by a OPTIONS keep-alive instead using ping tool. Anyway, he insisted and after a while the SBC started to drop ping responses.

First time we saw it was after a long burst from customer gateway. Then, we find that if we use ping command simultaneouslly, things got much worse and drop ratio increase.