Error when importing assembly stream

[Neintonine]

Heya,
If this problem has been solved once, I am very sorry.
I have an assembly, where I store a "glb"-file (had the same issue, with "obj", too) with some primitives.

The problem is, when I import the stream over "ImportFileFromStream", I get the following error message:
Assimp.AssimpException: 'Error importing file: BLEND: BLENDER magic bytes are missing, couldn't find GZIP header either
If I open it over paths, it's importing as it should.

I use Assembly.GetExecutingAssembly().GetManifestResourceStream("SMRenderer.Base.Models.Objects.SMDefaultObjects.glb")
to import the stream. At other importer, like SharpGLTF, I had no problems with the stream.

I am on Assimp-5.0.0-beta1 (latest currently)

I am happy for everyone, who attempts to help me.
Michel