UI glitches with Blur Image Effect

Hi there, I’m trying to blur the background of my game (on one camera with the Optimized Blur script) while having popups in the front (rendered by another camera on another canvas).

Works fine on PC and on my smartphone but not so much on my tablet and some other devices. Either the non-blurred UI doesn’t show up at all or it’s horribly distorted (see screenshot). Is there a way to make that image effect work consistently on all devices? Or is there a certain Open GL version necessary so I could build an alternative for lower ones?

Thanks in advance

Ok nevermind. I’ve set the 2nd camera to Don’t Clear… switched to Depth Only now it seems to work just fine.