In shaders, the behavior of accessing matrix values through indices is confusing

[Roogephy]

Your Godot version:
godot4_4
Godot Engine v4.4.dev4.official.36e6207bb - https://godotengine.org
WARNING: Can't obtain the XDG decoration manager. Libdecor will be used for drawing CSDs, if available.
at: init (platform/linuxbsd/wayland/wayland_thread.cpp:3731)
OpenGL API 4.6 (Core Profile) Mesa 23.2.1-1ubuntu3.1~22.04.2 - Compatibility - Using Device: Intel - Mesa Intel(R) Graphics (RPL-P)

Issue description:
in shader ,the mat4 and mat3 access through index is not the same behavior.
mat3 is:

but mat4 is:

so mat3 looks like column major order,but mat4 looks like row major order.
is this designed or a bug?
URL to the documentation page: