Happened to me on a 96 Southwind, a kissin' cousin of the Bounder. It is not a terribly unusual problem, especiali in older models. Nor is it a big deal to fix, as you noted. The front end of a motorhome is a huge fiberglass cap that is sort of tacked on and in most the windshield kind of floats in a rubber gasket set into the cap. It is subject to a lot of twisting action both as you drive (think about the turn and dip movement as you exit a driveway onto a road) and when the rig is jacked up on an uneven campsite. You should be careful when jacking to avoid any twisting movement, such as Ron described with a 3 jack system. Others claim that jacking the front wheels right off the ground can casue enough stress to pop a windshield. I suspect that any or all of these things contribute and can eventually casue a windshield to pop loose.
A few manufacturers tried to glue in the windsheilds to avoid this problem, but they experienced stress cracking instead, so most [if not all] use the free floating system. I haven't heard much about windshield poping in the last few years, so I assume the front cap designs have now been improved (stiffened?] to avoid this problem.