Quest 3 QR Code Tracking – Severe Position Jitter

Development Environment:
Unity: 6000.1.3f1
Meta XR Core SDK: 209.0.0
Meta XR All-in-One SDK: 209.0.0
Device: Meta Quest 3
Horizon OS version: 2.9

I am developing a mixed reality application for Meta Quest 3 using Unity and Meta XR SDK. My application uses QR code tracking to detect a physical QR code printed on paper and position a virtual UI button directly on top of it. The implementation was previously working perfectly. The virtual button remained stable, correctly aligned with the QR code, and fully interactable. However, suddenly, I started experiencing severe tracking instability. The virtual button now continuously jumps up and down (vertical position jitter). Even when I place the paper on a table and leave it completely stationary, the virtual button keeps moving significantly. This makes it almost impossible to interact with the button. What I have observed: The QR code is successfully detected. The physical QR code remains completely stationary. The virtual button continuously fluctuates. The button's position is no longer stable relative to the QR code. Interaction with the virtual button becomes extremely difficult. The same implementation was previously working correctly. Has anyone experienced similar QR code tracking instability on Meta Quest 3 recently? Could this be related to a recent Horizon OS update or a compatibility issue with Meta XR SDK 209.0.0? Has Meta introduced any changes to QR code tracking or pose estimation that could cause this behavior? Is there a known workaround or recommended fix? I would particularly appreciate feedback from developers using QR code tracking with Quest 3 and Unity 6.