BoneAttachment3D snaps to bone position only after reloading the scene window

[jwitz]

Tested versions

• Reproducible in 4.4stable and 4.3stable
• Not reproducible in 4.2.2stable

System information

Godot v4.4.stable.mono - Windows 11 (build 26100) - Multi-window, 1 monitor - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 4070 SUPER (NVIDIA; 32.0.15.6094) - AMD Ryzen 7 7800X3D 8-Core Processor (16 threads)

Issue description

When you configure Bone Name for a BoneAttachment3D node, the node doesn't update its position to the configured bone. It only snaps to the bone after you open another scene or otherwise reload the window of the scene which has the BoneAttachment3D node.

Moreover, if you configure Bone Name and then change the position of the node before changing the window, that transform is applied to the bone position, rather than the original position of the node. This means if you try to manually position the node to the bone, relaoding the window causes the node to be far away from your intial transform.

Steps to reproduce

1. Import a .glb file with bones into a scene
2. Make children editable on the node, then add a BoneAttachment3D node to the Skeleton3D node.
3. Select any bone for the BoneAttachment3D Bone Node setting. At this point, you should see that the node has not snapped to the bone as expected.
4. Open a new tab in the editor, then return to the scene. You should see that the node has now snapped to the bone as expected.

Minimal reproduction project (MRP)

minimumprojectbonebug.zip

[TokageItLab]

Should be fixed by #104209, please check latest dev.