Another Leaking Banjo Bolt

[lkt1954]

Installed a disc brake conversion kit from POL and I'm in the process of trying to bleed the brakes.
The only thing stopping me is the leaking banjo bolt on the drivers front caliper. I've tried 3 different sets of copper washers and not solved the problem. Every time, I tightened the banjo bolt as tight as I could with a breaker bar, still leaks.

In looking at the caliper, I have come to the conclusion it's a casting issue with the grooves where the washer goes. On the top right side the ring is almost smooth. I'm sending this picture to POL to see what they say.
Does this look like a casting issue anyone or is it just crappy copper washers?

Any thoughts, suggestions or ideas?

Thanks