I am using the Ad Sharing plugin on my multi site network. When users create a website (I am also using the Blog Templates Plugin) there are 2 ad units in the before content space. I have it set to only 1. When I disable the plugin at the network level 1 of the ad units goes away.
I am not sure what is going on. It looks like it is copying the code from the Template and then inserting an additional block of code as per the plugin.