TPO Roofs

I am currently in the process of purchasing a Grand Design 5th wheel. The issue of seam bubbles has come up. The roof is TPO. The bubbles are narrow but are the entire length of the substrate seam because there is clearly a gap where the panels come together. I have looked at numerous manufacturers installation specifications and videos. This is clearly a violation of the installation standards. These seams are supposed to be either filled, or covered with seam tape or both. In the case of these gaps, it appears to me that the manufacturer is indicating filling, but it isn't abundantly clear that the seam tape can't or won't work. Either way it isn't right. I have spoken with the factory person at Grand Design and their position is that these bubbles are not a problem and they seemed totally disinterested in the manufacturers opinion on this issue. So, where I am at this time is asking myself the question as to whether I want to accept this or not. I have looked at several other RV's and don't see the same problem. It appears that the roof membrane is well adheased down to a continuous substrate on other RV's. I am surprised that they seem so disinterested, but I have learned that TPO, and rubber for that matter, are tough enough that they are getting the warrantee life expectancy out of these roofs, which is only 12 years. This material when installed properly is possibly a 50 year roof material.