Yes, this one was one of a kind.. those black wires are joined under the tape with those same little clamp things!!
As for " heat damage".. I am not sure I did not get a good look at it but it would not surprise me.. there were a pile of 1 pole loads that could have been out of balance but there were 2 stoves, a dryer, garage sub and also a now disconnected electric water heater.. so chances are that service was WAY overloaded at one time.
The kicker is, if the homeowner would have done it correct and not "temporary" as he called it, the PoCo would have paid to have the service re-located to the front and supplied @200A.. The PoCo in this case PAID for the re-location BUT only an upgrade to 100A, if he wanted to go to 200A it would have cost him extra..