V71 seems to introduce a bug with handtracking that hands in the camera feed (and thus also the rendered model) are not aligned with your real hands when passthrough is enabled. You can reproduce this e.g. in "Demeo" when you switch between AR and non-AR mode that you're hands are "jumping" to the correct position as soon as Passthrough is disabled.
Could be related to the changes to eliminate the wrapping of your hands in the camera feed.
Strangely the PointerPose property of OVRHand seems not to be affected.
Having the same issues. I was also figuring this one for a while now and also came to conclusion that the breaking changes are coming from the v71.
It produces multiple issues but the main problem is that Controller Tracking Mode is brokenly prioritised even when only Hands are tracked. On Start the events coming from XRInputModalityManager are wrong, notifying that Controller mode has started even though it didn't and tracking input actions that have fallback to the Hand Devices will never fallback to them or will but only rarely.
The Hand alignment issue you are experiencing is also coming from this - your hands probably just use controller input values. I've had similar issues with headsets updated to v71 as well. Headsets that are not updated work fine on build, but lately even the unupdated headsets shown some issues when testing through Quest Link. I'm not sure why, maybe Meta Quest Link software also had an update with some similar issues like the v71 system version.
