When two View3D items live in separate windows and both reference the same StandaloneScene (e.g., the teapot sample scene) but use different cameras from that scene, only the first View3D reflects transform/position changes of models. The second View3D usually ignores transform updates (object positions appear frozen), though material/color property changes do show up. If both View3Ds are placed in the same window, everything works as expected.

Edit3: This is not reproducible in 6.9. 

Reproduction steps (minimal scenario)

1. Create a StandaloneScene with:

• • A simple Model (e.g., teapot).

• • Two distinct Camera nodes (e.g., camA, camB).

1. Create two QQuickWindows (or two top-level Window {} in QML).

1. Put one View3D in each window:

• • Both View3Ds set scene to the same StandaloneScene instance.

• • View3D #1 uses camera: camA; View3D #2 uses camera: camB.

1. Animate the model’s transform (e.g., position.x, eulerRotation.y) via NumberAnimation/Behavior/onFrameSwapped tick.

1. Optionally, also animate a material color to verify that material updates propagate.

Expected result

Both windows’ View3Ds render continuously with the animated transform (and material) updates.

Actual result

• Window 1 / View3D #1: Transform does update (animation visible).

• Window 2 / View3D #2: Transform usually does not update (model appears frozen).

• • Material/color changes do appear.

• • Occasionally the second view “catches up” or briefly updates after unrelated changes.

• Focusing / Resizing on window swaps the behavior.

Frequency

• Reproducible when each View3D is in a different window.

• Not reproducible if both View3Ds are placed in the same window.

• Intermittently, the second view shows a single transform update

A minimal example and a video is attached for reference.

Edit1: If we remove camera(s) from the shared standalone scene and add them directly to the scene of View3D (default-property), it causes a crash. 

Edit2: Adding any node to the "scene" default-property beside the importedScene causes a crash.