Steammachine not staying asleep due to Anynet+ CEC on Samsung TV

Device: Steam Machine (2026 Release)
OS Version: SteamOS Holo 3.8.23 (Build 20260715.2)
Kernel: 6.16.12-drmexec7-valve24.5-1-neptune-616-drm-exec-gf253f5da553e
TV Model: Samsung Frame TV 65" (Model: QN65LS03DAFXZC)
TV Firmware: T-PTMDAKUC-0090-213

Connection: Steam Machine connected directly to TV via HDMI 1

• Opted into Steam client beta?: Yes
• Opted into SteamOS beta?: Yes
• Have you checked for updates in Settings > System?: Yes

Steps to Reproduce:

1. Connect the Steam Machine directly to the Samsung TV via HDMI.
2. Enable Anynet+ (HDMI-CEC) in the Samsung TV settings.
3. Have the Steam Machine turned on.
4. Enable any combination of SteamOS CEC power settings (I have tested all permutations).
5. Using the Steam menu, command the Steam Machine to Sleep.

Expected Behavior:
The Steam Machine enters sleep mode and stays asleep. The TV either enters standby or "Art Mode" (Samsung Frame specific), depending on CEC power settings, and remains in that state.

Actual Behavior:
The Steam Machine initiates sleep mode.
The TV momentarily appears to go to sleep or enter Art Mode.
A few seconds later, the Steam Machine wakes back up automatically (the front LED light bar illuminates).
Depending on the specific SteamOS CEC settings, the TV will either wake back up with the Machine or remain asleep while the Machine runs in the background.

Troubleshooting & Workaround:

After extensive testing, I found that disabling the Anynet+ (CEC) setting entirely on the Samsung TV allows the Steam Machine to successfully go to sleep and stay asleep. However, this disables all CEC features (like using the TV remote to navigate menus or having the Machine control TV volume), defeating the convenience of a dedicated living room console.

Current Workaround:

• Leave Anynet+ (CEC) enabled on the TV.
• In SteamOS, disable the CEC option that allows the TV to wake the Steam Machine.
• Instead of using the SteamOS "Sleep" command, I use the Samsung TV remote to power off the TV. This sends a CEC sleep command to the Steam Machine, putting both devices to sleep simultaneously. Under this specific sequence, the Steam Machine successfully remains asleep.

Start by reproducing the issue with the listed Steam Machine, SteamOS build, Samsung Frame TV, HDMI connection, and Anynet+ settings. Compare each SteamOS CEC power-setting combination and the reported workaround; done means the Machine enters sleep and stays asleep while CEC remains enabled, without breaking the other described CEC behavior.