Roof damage on a Four Winds Chateau I'm looking to buy

So I'm looking to purchase a 2007 Four Winds Chateau Kodiak 32B (gas model). I noticed that the roof on the RV has some bubbling or air pockets on it. One area above the slide has some significant bubbling. I estimate the area to be about 4' x 1. I would attach a pic but I'm not sure how to do that. The owners said they have not one leak in a different area and it has been repaired. They have also resealed all the vents/AC on the roof. The area where i noticed most of the bubbling they said has never leaked. Is this damage a major concern or is it minor or even normal wear? If it does need to be repaired does anyone know what something like this would cost? I didn't notice any stains on the interior roof and I like everything else with the motorhome.

Thanks