I have experienced a case where LBS was unable to remove an Ofmega crank arm - their extractor tips (multiple tools)
were too large in diameter, hanging up on the top of the crank arm rather than sliding through to engage the crank spindle end.
They almost stripped out the extractor threads by exerting too much force.
My solution was to cut a piece of drill rod stock so that it extended beyond the end of the crank spindle. I inserted
the drill stock and then set the crank extractor tool so that it made contact on the drill stock, which was centered
in the spindle. The crank came off cleanly.
There is a residue of marking on the crank arm similar to yours.