When I put our slide out in January before we headed out to Arizona, the D seal was stuck to the slider and pulled away from the wall.
I noticed it, got out the ladder and unstuck it before it pulled all the way off, but could not get it back on the bracket because of the sealant/caulking.
I accessed that it was not a leak problem, so we went on our trip and I kept an eye on it when we put the slide in and out as we moved about to several RV parks along the way, and when I parked it for the winter when we got home I made sure that it was in place when I closed up the slide for the season.
I'll be replacing it this spring . . .