[Tweetstream & Facestream] duplicated tweets/updates

Hi, i’ve installed the last versions of these two plugins on my bp installazion (last version too… using wpmu).
Everything works ok, but sometimes (recently, a lot) twits/fb updates are posted more times, e.g. one single tweet sometimes is posted 2…3..4….8 (!!!) times in the activity on bp.
Ho can i solve this?
Thanks