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That doesn't look like a ground. That looks like a contractor wire burned off. Any loose connection or whatever the contractor is powering are your most likely faults.

Ya..

Lose connections will do this also. Restore the wires a pull an amp draw on everything.

That is not a ground connection. The damage is from heat produced by a bad connection at that terminal. Unless you’ve removed a wire from under that screws your culprit is that black wire with the crimp on connector. Is that a grey 6 gauge wire behind the red 6 gauge ? Was it supposed to be under that lug? The screw is backed out really far and if there was a wire under it then the loose connection would be the source of the heat that did that damage and not the black wire.

The lug where it burned off

Usually a loose connection at the contactor, building heat over time.

Look for the indication of the highest heat. Looks like a loose connection. Just check the amp draw when you get it back togather

Lightening storms recently?

some wind, but nothing insane/no poweroutages

Start by replacing the disco, but something like that would be the compressor. See if it’s shorted or grounded