Textures shuffling on their own

Hi everyone, I am looking for help to resolve a quite intriguing issue I have on my project.

I am setting up a virtual real estate tour, powered by lumen & nanite. I modeled quite a bit of furnitures & the structure of the flat in Blender. I have used a master material and applied instances on all the meshes, using textures i had laying around.

So here is the issue : everytime I start the engine or the build, all my textures / materials get shuffled around without any reason. Here is what materials should look like :


And here is the result in the build (each one is took after a rerun of the app):

I tried to flip feature switches that could impact in one way or another the textures/materials, like disabling texture streaming, changing sampler types and many other things but i cant get a stable result.

If anyone experienced something similar I would be glad to have a little help, thanks !