Now it no longer works with that port, is that right? I see you have reset the TV. Have you performed a hard reset with the soundbar? Try unplugging the soundbar for a few minutes and plug it back up.
I appreciate you going over all this with me. From the details provided, it sounds like this is a firmware concern. Unfortunately, we can't speculate when this will be addressed in future updates, but I will forward this accordingly.
Please test plugging in an external device to the Arc port on the TV and let me know if you receive a picture. This will determine if the issue is with the TV or Soundbar.