Obstruction or not?

[Illini_Ref]

OBR.

Bunt in the air down the first base line about 25 feet from the plate. Pitcher dives and touches the ball just in fair territory and it rebounds foul. Pitcher after he touches lands and slides into the baseline where the BR contacts him.

This happened today in the STL vs. KC game and I didn't see an obstruction signal by the PU (BR reached first safely). However, Fernando Vina got called for OBST a few years ago when as a second baseman he did the same thing between first and second, missed the ball and his subsequent positioning caused him to contact the runner. The said that as soon as he missed the ball on his initial attempt he was no longer protected.

Difference???