OP,(bsqrd) we really need to see what you have to know better, but I can offer this having done many roof jobs myself and then seeing others done by the RV manufactures. Mine often look a lot better then theirs, I'm not in a rush, they are.
There are a few reasons for the bubbles to show up when new and new could be months or a year or more after the camper was built. Here are some of them that I have seen/known how bubbles form.
I have seen this on EPDM, and TPO roofs. I have only seen one PVC roof so can't say they are better or not. I suspect the same issue can happen on PVC.
For a bubble to appear along a side molding edge, or out in the open area, the bubble happens "many times" (not all the time I'm sure), from lack of enough glue in that bubble spot. OR from not wiping the membrane down well enough to squeegee all the air out trapped between the roof decking and membrane by the installer before the glue sets.
A fresh wooden deck sucks up glue like a sponge. Warmer temps make this happen even faster. You have to put enough glue down to compensate for this wood absorption issue. And you have check you have membrane to glue contact completely. I'm sure plywood or OSB decking has some level of different absorption rates across the entire sheet, and sheet to sheet. And during application, the rate changes by the installer rolling it out. Again, you have to put enough glue on.
And there are fast set glues and slow set glues. The RV makers most likely use fast set as they want the glue dried by the time the camper exits the line. Since I am not up against a time crunch, I use the slow set glue. It gives me more time install and deal with what can happen before the glue sets. I can see the bubble issue happening faster with the fast set glue. If the glue is light in quantity and they do not act fast enough, the glue may not transfer to the membrane well enough.
If the air in not squeegeed out by the installer, that air pocket spot will not be glued down well. And while the glue may have been right, if the glue never transferred enough to the membrane in that small area, you can get a bubble. The bubble may not appear on day one. It may appear after the entire roof shrinks and the unglued area puckers from lack of being shrunk with the decking.
After the camper left the factory and some time has past, the membrane will shrink. And the shrink can flatten out the unglued bubble and it seems to disappear. It's still unglued, but shrunk tight and flat. The decking can/does also shrink and create some level of edge bubbles if the glue is light as there can be ripples there too.
The smaller bubbles do not leak as the membrane is intact. A very large bubble may be affected if it is very loose and can mechanically get torn, then you have a leak. I would be concerned on a large bubble pending how large, large is.
Again, this may not be the OP'ers case, just stated what I have seen. And yes, there are many new campers with roof membrane bubbles.
Hope this helps
John
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.
