Infield fly & tagging up

Question
My question is, infield fly is in effect, batter hits fly ball in infield and umpire calls infield fly, the runner occupying 2nd base takes a short lead and the shortstop is behind her to try and make a catch. However, the shortstop bobbles ball before making catch. The runner advances to third without any tagging up.  Is the runner also out if the shortstop touches 2nd base?  The ruling on the field was the batter was out becaause of the infield fly and the runner advanced at own risk and was safe because shortstop bobbled ball before making catch therefore the runner did not have to tag up.

Thanks,
RV

Answer
Hi Ramiro,

While a runner may legally leave a base as soon as a ball in flight is touched by the defense they have to be on the base when the ball is 1st touched.

That doesn't seem to be the case here and if F6 made a legal catch, R1 must tag up.  Bobbling the ball does not change anything

Mark