I have a runner on third – who returned to the bag once a pop up was hit just past the bag in foul ground. The fielder looking up to field the ball got tangled with the runner who was in contact with the bag. I ruled the runner had to give way to the fielder and thus imposed an interference call. The only time I thought a runner could remain on the base as a safe haven was during an infield fly.
According to OBR, seems it would be no interference (see below). The infield fly exception relates to being hit by the ball.
Rule 6.01(a) Penalty for Interference Comment: A runner who
is adjudged to have hindered a fielder who is attempting to make
a play on a batted ball is out whether it was intentional or not.
If, however, the runner has contact with a legally occupied base
when he hinders the fielder, he shall not be called out unless,
in the umpire’s judgment, such hindrance, whether it occurs on
fair or foul territory, is intentional. I