golf rule

Question
A player lifts a ball from a hazard to take a penalty drop but is unaware they have dropped it back in the hazard as marked by the yellow pegs. It did not roll to come to rest in the hazard. They immediately re-drop it outside the hazard to play as in the first instant they believe they are taking a penalty drop to be out of the hazard. This is a breach of the rules according to their marker. What rule has been breached and what are the penalties.

Answer
Dear ann:

Thanks for asking this good question.  I had to take some time for research.

In Rule 20-2 Dropping and Re-Dropping and b (Where to Drop):
A ball when dropped must first strike a part of the course where the applicable Rule requires it to be dropped.  If it is not so dropped, Rules 20-6 nd -7 apply.

Rule 20-6.Lifting Ball incorrectly Substitued, Dropped or Placed:
A ball incorrecly substitued, dropped or placed in a wrong place or ther wise not in accordance with the Rules but NOT PLAYED may be lifted, without penalty, and the player must then proceed correctly.

So, in your case I think there is no breach and penalty.

Thanks.