Post-process tint not working with r.Mobile.TonemapSubpass on Quest 3, UE 5.4.4 + Meta XR v71

Hi everyone,

I'm developing a VR project for the Meta Quest 3 using Unreal Engine 5.4.4 (official Epic branch, not Meta fork) with the Meta XR plugin v71. I'm running into an issue with controlling tone mapping and applying scene tints using post-process volumes.

Issue Summary:

• I need a post-process volume to adjust tint for a specific area via color grading.
• I followed the official Meta documentation for tone mapping (link) and enabled r.Mobile.TonemapSubpass=1.
• Even after disabling all post-process volumes (including those attached to my VR pawn), the scene is still globally tone mapped. When I activate my custom post-process volume, the intended tint effect does not show up.

Questions:

1. Is there a reliable workflow for toggling tone mapping, or controlling post-process volume tints (e.g. Scene Color Tint, Color Grading LUT) in a localized area on Meta Quest 3 with Unreal Engine 5.4.4?
2. Are there known engine/plugin bugs or limitations with tone mapping or post-process tint effects when using the Mobile Tonemap Subpass option? Is this issue present in the official Epic branch with Meta XR 71?
3. Are there any recommended workarounds or specific settings to enable area-selective tinting, or a timeline for fixes if this is a recognized problem?

Background:

• I have tested enabling/disabling volumes, used “Infinite Extent (Unbound)”, and tried runtime toggling via Blueprint and console commands.
• The problem persists both in-editor and on device.

Any insight, workaround, or official update from Epic/Meta would be hugely appreciated, as proper localized tint control is critical for my project’s visual design!

Thanks in advance!