OBS past base

[MD Longhorn]

Trying to avoid saying HTBT, but there are considerations here that make that hard to dismiss. There's no "always right" answer to your question without seeing the actual play.

First let me say that it is COMPLETELY reasonable that, especially at first base or the plate (where running straight through is a normal option), you can have obstruction on a fielder located behind the base.

Second, however, if you have F3 WITH the ball partially blocking BR's path, you'd better be 100% sure it was F4, and not F3 that caused any slowing or deviation on BR's part. If F3 is the reason for BR slowing or altering, you don't have OBS. If F4 is the reason, you do.

I hope that answers the question.