Baking artifacts on low (2.5k) poly

Hey!

This is my first ever bake and my result isn't the same as in the tutorials I find :(.

I am trying to bake this rather simple geometry for every maps except ID and normal. However it does this weird artifact no matter what I do.

I've tried :

Disablomg every map on by one. same result, no one map is responsible for this.

Upping the antialiasing. no changes.

Upping the output size. no changes.

Selecting : use lowpoly as highpoly mesh and then selecting again the same mesh in the source.

I don't see any problems with my UVs so I am at a loss. Any help is appreciated!