James,
Whew! Sorry on the delays for this. I just got into dive into the situation a bit more, and unfortunately, need to ask a few more questions. We did some testing, and couldn't recreate the problem. Additionally, our socialprofiles plugin for JomSocial does actually check that the last post isn't the same as the one attempting to be pulled in. That does mean that if the post in FB is further back in the JomSocial stream, it could be duplicated.. however, that really shouldn't happen if you think through it, since all posts from JS should go to FB, which means only the last should be duplicated... there are exceptions and possibilities where that would break down, but I don't think it's the 'general' case.
Now, our testing was using JFBConnect along with:
* the Social Profiles - JomSocial plugin. This is what would import the status *from* Facebook on login/registration
* The JFBC JS Activity - Community plugin. This is what JFBConnect uses to 'push' status updates in JomSocial to Facebook
In JomSocial v2.8, the option to push statuses to Facebook was added. I'm not sure if you're using that feature. If so, honestly, you shouldn't be. When using JFBConnect, you should disable the integration built-in to JomSocial, so that functionality shouldn't be what's 'pushing' status. If you are using that feature for some reason, it's possible our check for the 'same status' would fail (maybe an extra space or different encoding or something like that).
So, again, I don't think you should be using that feature, but maybe you are. If so, let us know.. and also, let us know if there's a reason you still want JomSocial's integration enabled when you're also using JFBConnect. I believe we do everything (and a lot more) for FB integration than JomSocial provides.
Either way, it's possible I'm testing wrong. I've definitely looked over the code much more thoroughly now though and can help investigate much, much quicker if we get more details on how to recreate.
Thanks for your patience,
Alex