Production LiDAR capture app affected by ARKit world-tracking drift on iOS 26.4+ (re: thread 827240) mitigation guidance and fix timeline?

Hello, and thank you for taking questions this week.

We develop DeepWalk, a production App Store application that captures LiDAR depth, RGB, and ARKit camera poses while field technicians walk continuous outdoor routes (sidewalk and infrastructure assessment). Recorded ARCamera.transform values are used downstream for 3D reconstruction, so world-tracking accuracy directly determines our output quality.

Problem: Beginning in early April 2026 and coinciding with the iOS 26.4 rollout across our device fleet, we observe directional, accumulating pose drift in recorded trajectories during normal walking motion.

The behavior matches the regression reported in forum thread 827240 (world-tracking drift on LiDAR devices on iOS 26.4+, absent on non-LiDAR devices running identical code). Link to existing post here: https://developer.apple.com/forums/thread/827240

Our configuration is minimal: a default ARWorldTrackingConfiguration with frameSemantics = [.sceneDepth, .smoothedSceneDepth] and no other options set, running on a bare ARSession with a Metal renderer (no SceneKit/RealityKit).

We measure drift directly from per-frame ARCamera.transform values, so the displacement appears in ARKit's pose output itself rather than in any rendering layer. The drift accumulates with walking distance and does not occur when the device is stationary.

We've observed this across a large variety of devices (iPhone 15/16/17 Pro/Pro Max) on all iOS versions 26.4 or greater. We've also observed this on iPad Pros with updated firmware. Thread 827240 additionally reports that disabling autofocus, HDR, and plane detection and varying scene reconstruction and world alignment did not resolve it.

Question Because depth capture is our core function, we cannot avoid engaging the LiDAR scanner, and we're not aware of a public API that adjusts its contribution to world tracking. We'd be grateful for guidance on three questions:

1. Is this a known issue in iOS 26.4 and later? Did the LiDAR contribution to world tracking change in that release?
2. For apps that require sceneDepth, is there any recommended session configuration, video format, or capture-side practice that reduces the drift in the interim?
3. Is a fix planned, and if so, should we expect it in an iOS 26.x update or the iOS 27 cycle? This affects how we manage our deployed device fleet.

We're happy to provide trajectory datasets, additional sysdiagnoses, or anything else useful. We have quantified drift-per-distance data across OS versions.