[Bug] Material not showing after upgrade from Iron to Jazzy

[firesurfer]

Description

We currently try to upgrade our stack from iron to jazzy. We mostly use stl files in our model. With rviz in iron all meshes + materials are shown correctly. In jazzy all meshes based on a stl file are shown in the same light gray (see screenshot)

Additionally rviz produces (Only in case the model is loaded via the moveit planning scene) and endless stream of such errors:

[rviz2-17] [ERROR] [1719212675.170806883] [rviz2]: Can't assign material Shape86Material to the ManualObject MeshShape_ManualObject7 because this Material does not exist in group General. Have you forgotten to define it in a .material script?
[rviz2-17] [ERROR] [1719212675.171172805] [rviz2]: Can't assign material Shape88Material to the ManualObject MeshShape_ManualObject8 because this Material does not exist in group General. Have you forgotten to define it in a .material script?
[rviz2-17] [ERROR] [1719212675.171424283] [rviz2]: Can't assign material Shape90Material to the ManualObject MeshShape_ManualObject9 because this Material does not exist in group General. Have you forgotten to define it in a .material script?
[rviz2-17] [ERROR] [1719212675.171593158] [rviz2]: Can't assign material Shape92Material to the ManualObject MeshShape_ManualObject10 because this Material does not exist in group General. Have you forgotten to define it in a .material script?

It is actually this stream of endless errors that makes it unusable.

System

• jazzy binary install
• rviz version: 14.1.1

Additional information

For most of these meshes a material is set in the <visual> block such as <material name="steel_blue"/>

EDIT:

I just ran rviz with '-l'.

Ogre does complain about:

08:17:31: Warning: Material file:///file_path_to_stl_file.stlMaterial0 was requested with isManual=true, but this is not applicable for materials; the flag has been reset to false

[chama1176]

I am getting the same error in my environment.
The material is applied to cylinders, etc., but not to stl.