In default configuration of FT231XS chip Tx and Rx LEDs indicate activity on USB side. Hovever for this convertor purpouse, we want to see Tx and Rx activity on UART side (connector). There for Tx and Rx LEDs are swapped (Rx led blinks when data is coming out from Tx PIN).
This problem can be fixed in SW configuration of FT231XS. Here is template.xml
for FT Prog.
Only change is swap configuration for CBUS1 and CBUS2 signals.