Why didn't the disciples recognize Jesus when He was cooking fish on the shore?
They did not recognize Him because His resurrected body looked completely normal and ordinary, not bizarre or strangely different. He appeared like just another human being, with all the outward appearances of a man, so they could not identify Him until the miraculous catch of fish prompted Peter to say, "It's the Lord!"
Les teaches that the disciples saw Him cooking fish on the shore, came up, and asked if He had any food or meat. He was very normal in all His appearances, so they did not know who He was; He looked like just another person. If Jesus had looked bizarre, weird, and different, Peter and the ten would have understood. Only when the net came full did Peter say, "It's the Lord!" At breakfast Jesus also ate with them, showing all the outward appearances of another human being, though He was now immortal. He could go through the wall or ceiling and be transported instantly, but He did not look weird or like a Hollywood concoction. His resurrected body appeared as normal as any human outward appearance during those 40 days from resurrection to ascension.