Duo System Not Working Correctly for Platinums with Diamons after ranked system changes

Before the changes plat three's were able to queue up with their friends in diamond 5, because you needed to be within three tiers of each other at diamond to duo, after the change if you are plat three, you can't queue up with someone who was diamond 5 before, because now they are diamond four, despite being within the three required tiers. Please fix so I can play with my friend during the preseason again.