Quality loss with copy/paste?

Hi to everyone,
i’m not an expert so sorry if i look so dumb, but when i copy an object from Sketchup, then open another Sketchup and paste it, it’s like it loose quality (numbers of polygons?).
Like in the screenshot, on the left the original object, on the right the pasted one, with more rounded angles, surfaces less flat, etc.
What am i doing wrong? why it’s so?
Thank you.

The copy looks like it’s softened. Is it copied into a group that is softened?

i’m sorry, as said i’m new in Sketchup/3D so i don’t know what a softened group is, where i have to looking for it?

Softening, Smoothing, and Hiding Geometry | SketchUp Help

SketchUp - YouTube search?query=soften