Gui.set_size cause a problem/glitch with texture on GUI (SOLVED)


I have a problem with simple progress bar. It behave kind a strange when it gets smaller.
Hard to explain, so I added the video and a simple project below.
Basically it is a texture from atlas with extrude borders. It has slice 9(but I try it without slice too). When I set its size smaller than 30, it start to kind a fade or blend in background.

Is this a bug, am I doing something wrong, is this about material or the compression/samplers? (52.4 KB)



Looks like Mipmaps cause this. When I turn mipmaps off it works just as I expected.
Is there a way of disabling mipmaps just for GUI?
I found it: