Nakamichi RX-505 Question

I'm not sure where to post this so I thought I would try this here. The above deck is auto reverse unidirectional model. Whether on play or record, the deck will at some point reverse itself without provocation. Annoying to say the least. Anyone have an idea what the problem would be?
If I understand correctly, the deck is flipping the cassette before it has reached the end.

I would hazard a guess that there is a mechanism which reacts to the resistance of the tape as it is pulled off the supply wheel by the transport. When the force required to do this is too great, the deck thinks the tape has reached the end and needs to be flipped.

Some possible causes of a malfunction here might be an overtight cassette, a worn or slipping drive belt or a weak motor.

If you are getting the problem even with cassettes you know are normal, I would say it's time to take the deck in to a Nak-savvy shop.
Yes. It's time for the Nak Doc. I would venture to guess it would be a belt, too. A general tuneup would be nice to make sure all is well. This is a great sounding deck and worth spending the money on.

It might not be a problem at all. Do you know about the auto reverse switch that is to the left of the cassette holder? It is a three position switch that allows for (a) single side play, then stop; (b) single side play, auto reverse, play then stop at the end, and (c) continuous play (i.e. flipping all the time at the end of the cassette).
I have the RX-202.
Let us know the outcome.

Whoops. Re-read your original post. I would have to agree with Tobias.