According to Mundo Deportivo, Barça has not yet officially announced Fati's departure.

It was previously believed that Monaco would exercise Fati's €11 million buyout option and had already reached an agreement with the forward, but the deal has yet to materialize. After consulting relevant sources about the delay, Mundo Deportivo learned that Barcelona wants to retain control over the academy player's future because the club believes his economic value is higher.
With Barcelona signing left winger Anthony Gordon for a fixed transfer fee of €70 million, Fati has realized that he cannot remain at Barcelona. Although his contract with Barcelona runs until 2028, Flick does not include him in his plans, and Fati has agreed to accept Monaco's offer. He spent last season on loan at Monaco.
The deadline for Monaco to exercise the buyout option is June 30. The issue is not only that both parties need to negotiate Fati's high salary, but also that Barcelona do not want to completely lose control over the player's future. Barcelona do not want Fati to join Monaco at a low price and then be resold, potentially ending up with a direct competitor.
Therefore, Barcelona's hierarchy hopes to include a buy-back option or other clauses, such as a percentage of a future transfer, to retain some control over the player's movements. If Fati truly reaches the top tier of professional football in the future, Barcelona will not face criticism for it. There is also another reason behind the delay in the deal: waiting for a higher offer. In any case, the matter remains undecided, and the outcome could still go in any direction.
This is also why Barcelona has not officially announced it yet, and some operations have been affected. Fati's departure will not be the only adjustment Barcelona make to complete the ambitious operations in Deco's hands. Fati came through Barcelona's youth academy and once inherited the No. 10 jersey left by Messi.
