LED Lights Switch Burned?

I had noticed my two LED lamps on my personal vehicle weren't working. I had found a loose connection and repaired it. I have in the setup an inline fuse of 30A from the positive terminal to the relay, a Novita RL44 40A relay, and a Dorman 20A rocker switch. Everything was previously wired properly as I had used the light setup as is for several months, and the lights worked again when I repaired the loose connection. As I turned the switch off, however, I heard a pop come from the switch and it began to smolder. The wire feeding power to the relay, which was connected to the positive terminal on the battery, became very hot. I cut the three wires feeding to the switch before further damage could occur, but the switch itself had melted.

Could this be the result of a switch that just so happened to have a defect that took action as I repaired the loose connection from before? Should I change anything in the setup, or simply get a higher amp/different brand switch? I am certain there are no breaks in the wires that would cause a short.