Shapes are not rendered correctly on some android phones

In a new empty project, with just the Shapes plugin installed, no other changes, I've created a rounded rectangle in the inspector. The build is working fine on most phones, but on some the result is very weird, the shape being distorted.

I don't know if it's related, but I'm building with openGLES 2.0 only. On some older phones that only support openGLES 2, this problem does not occur. There are no errors or warning in the build.

Any help is appreciated, maybe I'm doing something wrong, or it's got something to do with the hardware of these specific phones. In this case, is there something I can do to exclude these phones from running the game?