Yes I think it would be by chance that it landed there. They flew out of Mildenhall in the UK typically and flew all over the continent during the Cold War but weren't really set up to be based in Germany. The plane used a special fuel mix that wouldn't normally be available at every base and the security just to house the plane would have to be planned for typically so I'm guessing you're right, they probably had a technical problem that forced them to land there.