Good observation! The lump is actually a spot where the tread is separating from the casing. The casing is is holding up great which is why I want to get many more miles on this set. I've only flatted once on the road with this set, put on my butyl spare training tire, but once home I used the Stans and remounted the tire. Works like a charm. (well two months later I needed to refresh the sealant).
So shoe goo is the way to go? I was just thinking vulcanizing cement like in the patch kit. Thanks!