I also have several Patagonia jackets that are peeling or delamination on the inside. Patagonia customer service (via Chat) was most helpful. See the excerpt from my chat log below...
So we will process it, like a regular return, you mail us your jackets and we do a quick warranty evaluation once we receive the package and from there we go ahead and give you some merchandise credit. (Typically we go by the price of sale that we had the item at originally, so whatever you paid for the jackets is normally what you'd get in merch credit.)
So the way it goes, typically is, if you have the original order numbers from the gear you bought(if you bought online) you can submit the order number/your email and we'll send you a return label, to ship the package to us with your gear, once we inspect the gear(to ensure it is ours, etc) we deduce the damage is from wear and tear; we begin issuing you a credit. then (in a few business days) you will receive an email with a gift card code; the gift card code will have the balance of the refunded gear on it.
Now, if you don't have the order numbers if you got the gear as a gift or bought it from a store etc.; it’s no problem; there’s a form you can fill out; ill send you the link in a moment and the rest of the process is the same.
Patagonia Returns Form - Warranty