ED coating does not assure protection against corrosion - it does not produce a complete, uniform coating on 100% of the the tube interior surfaces. Surly started using ED coating for all their framesets several years ago, and yet they still recommend use of an internal corrosion-inhibiting treatment:

"Pugsley frames also come with an internal ED coating. This is a process that coats the frame inside and out with a protective layer to provide a foundation for the finish and give an added level of protection from corrosion on the inside of the frame. We still recommend treating your frame with a protectant such as Framesaver or Boeshield".

https://surlybikes.com/bikes/legacy/pugsley_2016