It is truly shady but you know that the world organizations like this, including world bank, United nations are heavily influenced by the United States.
Also the namt IMF is not what they should be called, they supposed to be called IFF which mean International Fiat Funds. And the dominant fiat is United States dollars.
Even if the accusation is true, why should the IMF make this finding public? The organisation would be protecting some nations, but they just want to discredit El Salvador and shame them before the committee of nations.
However, if this claim is true it shows that Nayib Bukele has stained his reputation. It shows that some of the reports of financial misappropriation, disrespect for human rights, and suppression of opposition might be true.