Some clay chip manufacturers press chips twice during the manufacturing process. The first time is to solidify the slug (consisting of raw cut clay plus the clay inserts/spots), and the second pressing is to add the inlay and final mold markings.
This is typically done to quickly create a large number of (spotted) blanks, which are later used to create a variety of chips (sometimes with different inlays and/or mold markings, sometimes not). It's sort of the clay chip version of a production line, performing dissimilar steps separately to increase speed and minimize opportunity for errors.
Done correctly, any mold markings from the first pressing will disappear and be replaced by the markings of the mold used in the second pressing. If temp/time/pressure is not correct, the markings from the first pressing may remain (referred to as ghost marks or ghosting).