Just posting to say that there is an extremely simple workaround. I have this setup, and all it took was 30 seconds to file a very small V-notch in the optic mount, to have it seat properly. See, the end of the fire sight comes to a point, and it's the last bit of that point which gets in the way. Very small bit. So you can take the sight off & file the point back, or file a small V-notch in the optic mount before you put it on; in the pics below, you can see how small it is - it's also at about a 45° angle, so only extends a few mm underneath. Either way, a dab of black rust paint covers it up.
[edit] snapped 2 quick pix