Zuzana,
It’s interesting, when I try to find the texture settings for the original, spotty model at the top of this post, RC doesn’t list the settings I used. It says “unknown”. It also says texture utilization 0%. There is a little “tx” next to the model indicating it was textured, and I can render out views that appear textured, but the info window is strange.
Is that a clue? Here are the settings for that spotty model: