Nope. One of a few annoying "features" that this otherwise brilliant device is endowed with. It's a perfectly natural usage mode that it would have been capable of, had it simply been defined by design.
There are some workarounds, but they're just that. For instance you could record silence just to define the loop length (wherein already lies the compromise). Stop the loop, and when you next hit record, the first, second and ensuing passes will be in overdub mode without a transition.