In the file enc_as504x.c, there is the definition of the registers addresses as:
#define AS504x_SPI_DIAG_ADR 0x3FFD
#define AS504x_SPI_MAGN_ADR 0x3FFE
#define AS504x_SPI_CLEAR_ERROR_ADR 0x0001
This is correct for the AS5048A encoder, BUT for the AS5047P the correct addresses are:
#define AS504x_SPI_DIAG_ADR 0x3FFC
#define AS504x_SPI_MAGN_ADR 0x3FFD
#define AS504x_SPI_CLEAR_ERROR_ADR 0x0001
In vesc-tool if you select the AS5047P the driver called is this one: enc_as504x.c, so you will have troubles for sure. This issue is here from the beggining and as the normal setup is to connect the MISO to Vcc, this problem is masked. Sometimes it works, but sometimes it does not, and you will get crazy for sure.
I think that this shall be taken into account as soon as possible in the firmware.
I will open an issue in the github repository