Resolved! STM32WBxx spi HAL driver seems buggy when transmitting in 8 bit modes (not interrupt nor DMA driven).
In STM32Cube_FW_WB_V1.12.1 the function HAL_SPI_Transmit() increase buffer point per sizeof(uint16_t) when sending data in 8 bits mode; this lead to 1 byte every 2 bytes not being send out. See the below snippet from HAL_SPI_Transmit() /* Transmit da...