Today I switched out an receptacle and when I turned the power back on and checked the outlet with my receptacle tester, everything was good. I switched out another receptacle with no issues that is on the same circuit and then checked both of the receptacles again. This time when I tested the first receptacle, a spark flew and the circuit was tripped. I am not positive, but I think I tested the second outlet on that receptacle this time.
You can see that the second hot terminal is the one that is burnt. Also, the I took a picture of the original receptacle along with the new one. The other odd thing is that the original receptacle had the hot wire attached with a wire nut and an extra inch of wire, even though there is plenty of wire in the box.
Any thoughts about what happened and what needs to be done?