Hello ,
When working with materials in Twinmotion they are scaled based on the UV mapping of each element. Thus if all those placed assets had a different original texture applied with different size/mapping applying the same Material in Twinmotion will show different sizes.
In order to help restore the mapping you will need to reapplying the material using the correct UV mapping corresponding to that shape . See example below with simple primitive shape from library and a square imported with Direct Link composed of different materials.
Hope this helps.
Kind regards,
Vincent B.