“Mommy, can I do anything to help you with Pesach preparations?” asked Shoshana.
“Sure! So nice of you to offer,” said Mrs. Hirsch. “Hmm...let me think how you can help now. Oh, I know!” Mrs. Hirsch reached into her purse, took out her wallet and handed some money to Shoshana. “Here, take this money, go to the supermarket and buy 4 kilo of brisket meat for Pesach,” said Mrs. Hirsch.
Shoshana ran to the store, bought the meat and brought it to her mother. “Excellent! Thanks so much, Shoshana” said Mrs. Hirsch. As she looked at the package of meat, she said, “Before you went, I completely forgot to tell you which hechsher we need. But fortunately, you happened to buy meat with the best Kosher l’Pesach hechsher in town!”
Before Yom Tov, Mrs. Hirsh made a delicious brisket from the meat that Shoshana bought and served it the next day, at the Yom Tov day’s seuda.
Question: Who in this story did something halachically wrong?