Can't set E22-900M22S to sleep

I have an E22-900M22S ebyte module connected to an ESP32 board. Upon issuing the sleep command from a standby state, the module consumption stays the same. It is around 545µA, which is consistent for the standby mode, but do not drop any further down after the sleep command. I have tried multiple ebyte module and also 2 different ESP32 board, same same.
I am using the RadioLib and the modules are capable of transmitting and receiving.
The SPI bus stays active during the life cycle. Any idea what could be the cause?