Hi there,
we made some Facebook Campaigns which have a bounce rate between 0% an 5% which seems to be great but cannot really be true. It looks like a bug. what is the true meaning of this? 
Can you check in your Visitor Log, segment user who come from Facebook, and see how their visit look like? maybe they do visit many pages, maybe your website is most interesting or maybe they could be bots, or maybe a bug somewhere…