Well, when my Fiance went to his interview in Jakarta in 2021 and he was told the K1 visa was approved, they kept his passport and he stayed in Jakarta, ( he lives in another city in Sumatera,) and they did not give a receipt. He was not concerned. Five days later he received the notice that the package was delivered to the pick up courier and he picked it up. In 2023, as my spouse, the same thing happened, he went to the interview in Jakarta, his visa was approved, they kept his passport, no receipt given, and 5 days later he picked it up at the courier. He stayed in Jakarta in a hotel for the time waiting and had no concerns.