Jam scum after sealing
Did you skim the scum during cooking?  Also, sealing with wax is no longer considered safe, especially if you plan to sell the jam.  It's possible that what you see is mold and not scum.

http://nchfp.uga.edu/how/can_01/prevent_spoilage.html

You might be able to save your batch, if it's not moldy if you throw away the wax, and reprocess in a water bath canner using lids and rings.