Using TTL and USB

This community has been very helpful so I am hoping to get some insight.

Due to the EOL, I switched to Particle. I have two setups, one using a CH340 USB-TTL converter and the other a genuine FTDI cable.

With the USB cables connected, if I recycle power to the micros, the CH340 setup immediately restarts. However, the FTDI micro does not restart unless I disconnect the FTDI cable.

I am sure it is no a power supply issue because in the case of the FTDI cable, the micro is definitely getting power and was verified.

What could be the cause?

Thanks in advance.