Mixed metaphors? Incoherence? Dylan?
Read it twice. It's even funnier the third time. The key is in the unarticulated relationship between the two parts of the sentence. Is one of them supposed to be a dependent clause?
"Obvious as [Bob Dylan's] talent may be, he often mixes metaphors and combines images in a way that skirts the edge of incoherence."
If you can guess who wrote it, you may win a brand new leopard-skin pill-box hat. Or not.