Xi6-T outputs Dolby Vision on SDR content

Issue: Xi6-T outputs Dolby Vision on SDR content (LG OLED65E9PUA, 4K60 mode)

Device setup:

• Xfinity Xi6-T cable box
• LG OLED65E9PUA
• Direct HDMI connection (high-speed certified cable)
• Xi6 output set to 2160p60 (4K UHD best available)

Problem:
After viewing Dolby Vision content, the Xi6-T remains locked in Dolby Vision output mode on all subsequent SDR/1080p channels.

When this occurs:

• LG reports Dolby Vision active on SDR/HD channels
• SDR content displays with incorrect/oversaturated colors
• LG does not allow manual exit from Dolby Vision mode while the DV flag is present

Conditions:

• Occurs consistently at 2160p60 output
• Does NOT occur at 2160p30 output
• Triggered after Dolby Vision playback; device fails to properly return to SDR signaling state

Workarounds:

• Power cycling the TV (forces HDMI renegotiation) resolves the issue
• Changing Xi6 output resolution:
  • 2160p60 → 2160p30 → 2160p60 immediately clears the stuck Dolby Vision state without TV reboot

Isolation steps already performed:

• High-speed HDMI cable replaced
• Multiple Xi6-T units tested with identical behavior
• LG OLED operates normally with other HDMI sources

Conclusion:
Likely Xi6-T firmware/HDMI output state issue related to Dolby Vision → SDR transition at 4K60 output mode.