We're looking at this ticket guys but we need more info:
What version of JomSocial are you now using and seeing this? My hunch is that JomSocial is outputting a module position within the component itself. Is this position configurable to sidebar-a? If you publish a module to 'left' or 'right' position does it display? I'm not sure how this issue could be an issue on our end, its much more likely its a JomSocial limitation.