The DicorProducts.com website says the EPDM roof membrane is actually made by Carlisle Syntec and may be warranted by Carlisle Syntec. Perhaps Carlisle Syntec might be more accommodating. It's probably worth a call.
Here's a link to the website.
There are a couple of challenges to getting help. The Dicor warranty repeatedly uses the phrase "to the point of failure", which suggests that they don't have to provide anything if the roof hasn't failed. Is cosmetic damage equal to failure? I'd guess by saying cosmetic, they are making the point that they don't consider the roof to have failed in its primary purpose.
The next level of challenge is that even if they agree that the roof should be considered to have failed, the warranty remedy is to provide you with new roofing material. The cost of the material is a very small fraction of the overall cost of replacement. Getting them to pay thousands of dollars in labor charges is a whole different matter which probably requires them to grant you an accommodation, as opposed to warranty coverage.
Something else to consider is that when the roof material is replaced, it's a very invasive repair action. air conditioners, vents, skylights, ladder all have to be removed. The membrane is cut at the front and rear caps, creating new seams that require careful maintenance. The thin luan layer under the membrane is likely to be damaged by pulling up the membrane, requiring sanding and new luan. At the end of the process, you'll have a more attractive roof, but it won't be equivalent to new.
As a trade or resale, having a roof replacement is probably a step up from where you are, but it probably will still cause the value of the trailer to be discounted. Sometimes people don't disclose things like this, but if there's ever a problem, it will become obvious that the repair was not disclosed.
If it were me, based on your description and pictures, I'd go for the new roof if Dicor or Carlisle would agree to pay. So the trick is to get Dicor or Carlisle to step up and make you as whole as possible. If it's actually a manufacturing defect, and Carlisle made the membrane, perhaps they would be most likely to help.