"General" (not alpha) insider update disables HDMI passthru?

When using passthru on sound bar, are you using an hdmi 2 cable(one rated for 4k60), and have you checked the soundbars settings, somewhere in there there should be an option to set the passthru hdmi port to 4k(if it supports it)

This was a known issue with consoles enrolled in the Alpha Skip Ahead Insider preview.

Is your console enrolled in a Insider preview? If so, download the latest OS update.

Check Xbox Insider Forum on Reddit. This forum is for General release OS.

The "new" Edge is currently only available to Alpha Skip Ahead Insider preview members.

Insider issues are handled by Reddit Xbox Insiders forum. This forum is for General release OS issues.

Edit.. As of 22nd July "new" Edge is available to Alpha, Beta, Delta Insider previews so it is getting closer to a General release.

Seems you have to be invited to join the Alpha ring

https://support.xbox.com/en-US/xbox-one/console/xbox-insider-program

The current Xbox One Update Preview rings are:

• Alpha – Open on an “invite only” basis and receives updates at the earliest point in the preview window.
• Beta – Open to Xbox Insiders with a Program tenure of 3 or more months and an Xbox Insider XP Level of 5 or higher. This ring receives updates shortly after Alpha.
• Delta – Open to any Xbox Insider with a tenure of 1 or more months that has reached Xbox Insider Level 2 or higher. Depending on certain edge cases where further attention is required from Alpha or Beta rings, Delta Insiders may receive
  system updates before Beta, though this is not a common scenario. Additionally, while early system updates are not guaranteed across the Delta ring, all Delta Insiders will receive the update prior to GA.
• Omega – Open to anyone and receives system updates shortly before the GA (General Availability) release.

I really wouldn't like to say yes to that as the Omega ring gets updates just before general release so the odds aren't good.

The current Xbox One Update Preview rings are:

• Alpha – Open on an “invite only” basis and receives updates at the earliest point in the preview window.
• Beta – Open to Xbox Insiders with a Program tenure of 3 or more months and an Xbox Insider XP Level of 5 or higher. This ring receives updates shortly after Alpha.
• Delta – Open to any Xbox Insider with a tenure of 1 or more months that has reached Xbox Insider Level 2 or higher. Depending on certain edge cases where further attention is required from Alpha or Beta rings, Delta Insiders may receive
  system updates before Beta, though this is not a common scenario. Additionally, while early system updates are not guaranteed across the Delta ring, all Delta Insiders will receive the update prior to GA.
• Omega – Open to anyone and receives system updates shortly before the GA (General Availability) release.

https://support.xbox.com/en-US/xbox-one/console/xbox-insider-program