Mine used to do this. I think there is a timer in it that somehow gets randomly set. For a long time it did not do it anymore. Then here a few months ago it did it again. I never use mine anyway, so I took it out and unplugged the power wire from the back of the unit. When I get home from this trip, I'm taking it out, and building a cubby into that hole. The 'ol Jensen will go on the shelf in the garage to go with the trailer if I ever sell it.
PS, just pulling the fuse is not a good option because there are other things on that fuse.