3D effect problem

Hello all,

First I am sorry for my english, I'll try to explain myself.

What I tried to do :

I have an image, I highlihted the text, and I want to create simple 3d effect.

But when I do that, I have kind of lines appearing

First I tough it was only before exportation, but it was still there on the final vidéo

Please see below.

Can you please help ?

Thanks you.