I wouldn't say its common, but it happens. I have a 2014 with no ripple. I put a high quality 3M Crystalline on windshield (70%) to reduce heat and UV damage along with proper annual leather treatments.Looking to buy my first Ghibli S. Saw two 2017s with dashboard ripple in the middle at the windshield. Is that a common problem? Any ideas how that would happen? The rippling was the same in both cars. I thought it might be due to sun exposure, but one of the cars had under 3k miles, so not likely. Do you know if that would be covered by the manufacturer warranty?
That said, the cars you are looking at regardless of mileage might have been parked outside in direct sunlight and not sure what area of country they were in?
The warranty would depend on how bad and dealer discretion ... certainly worth an ask.