iMac M1 (2021) Thunderbolt port inconsistency

Hi!

I have a 2 USB + 2 TB3/USB4 model.

The issue is external self powered TB drives not mounting after a Restart or Power on.

If my drives are plugged into the outside TB port (one to the right in the photo), they mount normally and there is no issue.

If they are plugged into the inside TB port, they will not mount. The drives need to be power cycled to mount. It doesn’t matter if it’s from a system restart/reboot or powering up for the first time. Without the power cycle, no drives.

Discovered this behavior troubleshooting other issues with this iMac….and there are many as far as a video editor is concerned. (use a Logitech MX Master 2S at your own peril with Premiere and Media Encoder)

What is the difference in the ports? Is this a sign of a defective port? I’m not finding anything that documents any differences in the ports. Since each one is its own bus, I can’t help but feel I have a defective port.