I have the same problem. The only solution I can use is to remove MESHES (materials, textures, etc. DO NOT DELETE) from the content browser , save all, import and you have old FBXscene blueprint, R click - asset action- select actors using this asset. You will receive your materials and coordinates, but you will need to add meshes in the details window. If you have a small number of meshes, but you need to save coordinates and materials, it will be faster than deleting everything and reloading it