First two byte of Transmit Buffer sent by STM32 to Motor Controller is transferred wrong
It seems like you have some sort of 7/8 bit format mix-up in your STM32. The difference between the expected and unexpected data is that the MS bit is set. For example, 0x03 vs 0x83 in: ( bf 27 30 33 20 31 0d ) "¿'83 1\r"

Your message format seems to only require 7-bit ASCII values. Study the UART specifications for the STM32 to see if there is some distinction between 7 bit and 8 bit data operation or setup. Also, try ANDing all byte values with 0x7F just prior to loading them into the UART's xmit data register.