What constitutes an "attempt to advance"?

[PandaBear]

Situation arose on a catchers interference call under NFHS rules.

In the play, the batter put the ball in play as a fair grounder, but was put out at first. R1 broke from 3rd (unforced) upon the ball being hit, before I had time to signal and verbalize obstruction, and scored on the play.

8-1-1 e 1 states that "Any runner attempting to advance on a catcher's obstruction of the batter shall be awarded the base he is attempting."

HOWEVER, it also states "If obstruction is enforced, all other runners on the play will return to base occupied at time of the pitch [excludes when forced to advance]. The batter is awarded first base, if he did not reach base."

Is attempting to advance unforced on the play considered "attempting to advance"? The rule identifies examples of attempting to advance to include steal or squeeze "(i.e., steal or squeeze)", but that seems to be a statement of examples, and is not to be considered an exclusive or comprehensive list of acts that are considered "attempts to advance".

Obstruction was enforced (at coaches option), and the batter awarded 1st base (out nullified), but the point of discussion and confusion was whether the runner's advance should also stand, under "shall be awarded the base he is attempting" clause, or not, under the "all other runners on the play will return to base occupied at time of pitch" clause.

These clauses are semantically in conflict, and the current case book offers no clarification. Consultation of another rule code that happens to have the same effective language (probably modeled after NFHS) unfortunately also didn't offer any clarification on this point either.

Has anyone seen clarification or an interpretation on this matter?