were did the epoxy come from! Whats up!! are you sure you have the plugs for your engine you might have bought plugs that were too long. Pull all your plugs and make sure they are are all the same length might have a wrong plug in the packageWhy would somebody think epoxy did it? It COULD have if a piece came loose and got pinched in the wrong spot.
Looks like someone was too lazy to blow out the s**** from the plug well before a plug swap. Short cuts will cost you in the long run don't be lazy do the right thing the first timeLook at the small rocks stuck to plug in pic and could be trash fell in plug hole on the previous goround if there was one. Why I always airblow those plug ports out before removing plugs. Don't put face over the work, you can lose an eye with the size of some of the pebbles that come loose.