I don't know the situation you described, but this is the rule:
Rule 6/13
o. When a stoppage of play in an end zone takes place and is
followed by an altercation (wheather a penalty i called or not),
an attacking player on the ice or other player coming from the
becnh shall not enter the end zone farther than the outer edge
of the face-off circles nearest the blue line.
PENALTY -- Face-off at the nearest neutral zone face-off spot.
Obviously this is a judgement call by the refs -- was it an "altercation"?
Where where the players before the whistle, etc.
--david