Double Precision MultiMeshInstance3D does not Scale Properly

[mschwarz1]

Tested versions

• Reproducible in: 4.4.dev.double [bdf625b], 4.1.dev.double [dbcc7f3]. (I didn't personally check but @Zylann said it was also reproducible on a double precision build of Godot 4.3.)
• Not reproducible on single precision builds.

System information

Godot v4.4.dev.mono (e369ef6 (Really bdf625b)) - Windows 11 (build 22631) - Multi-window, 2 monitors - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1080 (NVIDIA; 32.0.15.6590) - AMD Ryzen 7 3700X 8-Core Processor (16 threads)

Issue description

Expected:

multimesh_expected.mp4

Actual:

multimesh_actual.mp4

In double precision builds of godot it seems like the scale isn't being applied properly across the individual mesh instances within a MultiMeshInstance3D. The scale gets applied but the positions/origins of the instances aren't affected at all.

Steps to reproduce

Included is a MRP. In the MRP just open the one scene and attempt to scale the MultiMeshInstance3D or it's parent cube. The parent is unneeded but it helps illustrate what it should look like since when scaling it the cubes should stick to the surface of the parent cube.

In general the steps to reproduce are:
1.) Run a double precision version of godot.
2.) Create a new scene and populate it with a MultiMeshInstance3D.
3.) Populate the MultiMeshInstance3D where each instance has some offset.
4.) Attempt to scale the MultiMeshInstance3D and observe each instance's position not change.

Minimal reproduction project (MRP)

multimeshweirdness.zip