Inadvertent whistle?

[Brian26]

Rule states is penalty during play in which you have a inadvertent whistle takes precedence and will be administered is accepted. The covering official throws the flag and blows his whistle right after thinking play was dead would the rule still apply?

[HLinNC]

Fundamental III 2.  "No live ball foul causes the ball to become dead." 
The penalty would be assessed and the down replayed, unless it was a loss of down foul.  The IW would be ignored.

The flag doesn't cause anything.  Lack of rules knowledge or a complete brain fart by the covering official causes it.

[Brian26]

Fundamental III 2.  "No live ball foul causes the ball to become dead." 
The penalty would be assessed and the down replayed, unless it was a loss of down foul.  The IW would be ignored.

The flag doesn't cause anything.  Lack of rules knowledge or a complete brain fart by the covering official cause it.

I explain that wrong about the flag causing the play to be dead. He's first year official and he knew he made a mistake right after. Just wanted to make sure since it happened at same time the penalty would still be enforced.

[bossman72]

Rule states is penalty during play in which you have a inadvertent whistle takes precedence and will be administered is accepted. The covering official throws the flag and blows his whistle right after thinking play was dead would the rule still apply?

Yes.  The foul happened the instant before he blew his whistle.  It did not happen after the whistle.

One of the most common is new guys will blow dead an illegal formation or illegal shift. 
If they do it before the snap, we can wave it off and reload. 
If they snap the ball, then the whistle is blown, we can enforce it, since the foul occurred the instant the legal snap happened and the play was killed inadvertently immediately after.