I won’t bore you with the details, but electrical engineers call it “crosstalk.” Signals leaking in to where they ain’t supposed to be. When they make ‘em they precisely calculate azimuths for the recording heads or the signal gets screwy. Complex geometry goes into this: everything from Euclid to Turing.
But this Betamax player? Uniquely fucked. The angles are just the right kind of wrong, so we get crosstalk.
But the signal isn’t leaking in from the other part of the magnetic tape. You get it? It’s coming from somewhere else. Somewhere the angles don’t even work the same.