They bailed on Patton because it's cover 3. Sherm knew he only had Crabs to his side and that's why it looks manned up. That's also why the OLB bailed and was helping underneath. They had no one threatening his zone so he ran towards the only WR on his side. He was coached up awesomely because most LB's would just sit like a dummy and look for a crosser.
This is especially on Kaep because he should've KNOWN it was cover 3 and that the weak spots are the short flats AND it's on Harbs for not calling more routes under Crabs to flood the zone. If you're going to make Crabs the first read in this play he should understand his QB doesn't often move his eyes from one side of the damn field to the next and at least had Frank pull the eyes of the LB so it's just an incomplete rather than a pick from deflection.
I can't disagree here.