I would think that the crust on the bottom of the kettle would contribute more funky flavors to your beer than the elements (judging by the picture). It looks like you had more scorching problems when using propane! Do you not clean between batches? Are those high watt density elements?
If you say that the beer tastes awesome, I don't think you have "bad" scorching. Bad scorching, IMO, would impact your beer.