The white inner liner glaze (that wraps over the rim) was not removed after the wax was applied. The outer glaze thus overlays patches of it near the rim. The meeting line has been blurred and the other glaze has run downward and crawled somewhat revealing patches of the inner one.
Liner-glazing ceramic ware is a very good way to assure that your ware has a durable and leach resistant surface. It also signals customers that you care about this.