Double posts between sites and buddypress on a mulsite install

Hello,
Using buddypress on main site and blogs on subsites, i have noticed the following :
1) when I make a post on a subsite. I am having a reccord on the activity stream, which is veary good ! :slight_smile:
But 2) When I am responding to a post from buddypress (comment) I am having a double comment entry in activity stream. the comment is sent back to the blog on the subsite, which is also good, but I guess I am receiving an activity stream back.. as well, which makes the comment to be written in double !
Any ideas how to fix this ?
Best regards,
Hervé