I noticed mine while riding my motorcycle in front of my wife with our rig. Mine was rising up about 2ft and was from the front to almost the front bedroom a/c. You could see the rubber roof was loose although it layed flat when the rv was stopped. I just called a mobile rv tech who said he had fixed several.
He removed the front cap seal at the front of the roof. He showed me where Forest River only installed about 1/3rd of the screws. He showed me where about 6 ft. of extra roof rubber was laying inside the front cap. He said they don't bother to cut it off at the factory.
The RV Tech said air comes in from under the 5th wheel hitch into the front cap. It will get under the rubber roof and past the cap seal and raise the rubber roof up.
He cut off the excess EPDM roof beyond the front cap. He glued the roof back down and installed an extra cap seal with ample screws to ensure the air doesn't get under the roof. He charged $400 and I have not had any problems with it in the 6 years since.