Erratic behaviour in iOS Metal when using layered cameras

Unity Version 2019.1.0f2. I have several cameras (lowest one has solid color clear, other clear depth) that are used to compose a 3d scene with camera canvas and world space canvas. When I try to use Metal API in ios device the output is erratic, sometimes the background layer is not updated at all, and sometimes depth-clear cameras clear color from lower cameras as well.
Resorting to ES3 is partial solution (everything works there) but I am curious how Unity claims to even support Metal if it does behave so erratically. Also getting some CPU benefit from metal would be nice, and metal plays more nicely with xcode frame debugger as well.

I have 2x msaa enabled in the scene.
My issue seems to be related to this (still open bug)