Bump because of time sensitivity.
I have experienced some odd things like this because of vector masks. Maybe delete that vector amsk on the layer set mask and see what happens. If that doesn't help I would copy all of the base elements to a new doc and start over with the warp. You might even change your new doc canvas size a little in case it's a bug due to the warp + canvas size relationship.
Just a couple of thoughts.
Thanks for the suggestions. I couldn't come up with any one method to fix the problem. I tried different documents, building the asset without masks of any kind, smaller resolution etc. It did the exact same thing every single time.
I finally just settled with using the other Warp transform method since I ran out of time for delivery.
I'll keep a lookout for anything that may cause this in the future, but it sure is frustrating.