Fake tag and no retouch

[TriggerMN]

Fed rules.

R1 on 1st, 1 out. R1 takes off for 2nd base on hit and run, and batter flies ball to right-center. F6 fake tags R1, who then touches 2nd base and rounds towards 3rd base. The ball is caught by F9. R1 runs back to 1st base without retouching 2nd base, but is retired at 1st base.

Dead ball now, R1 receives 2nd base because of obstruction by F6.

Now...once the ball becomes live, can the defense appeal the missed retouch of 2nd base even though R1 is now STANDING ON 2nd base? R1 did not retouch 2nd base before the ball became dead. Or does the obstruction supercede the missed retouch? Does it matter if the fake tag by F6 occurs before or after R1 has touched 2nd base?