Obstructed runner retreating after reaching awarded base

[greymule]

I remember an ASA case play in which a runner is obstructed between 3B and home, gets trapped in a rundown (or gets trapped in a rundown and then is obstructed), but makes it safely back to 3B when the throw gets away from F5. The runner then tries for home and is thrown out. The ruling was that he was protected between 3B and home even though he had returned and touched 3B. So he is awarded 3B. (Of course, that's not the next base, but . . .)

As I remember, an exception to the blanket protection between bases arises if there's an intervening play.

A few other cases are mentioned in this thread, which dealt mainly with a different issue:

subsequent play on different runner