Onyx Ring Discussion

Ugh, this game's critical mechanics are confounding.

I got the maximum critical damage ring on my Dual Blade and when I equip it, he's gaining +10% to minimum instead, even when I replace his current Critical Adventurer ring with it. He already hits the minimum critical cap without equipping either, which is why I assumed the +10% minimum from the adventurer ring currently goes to maximum damage due to "spillage".

So currently,
+10% minimum from Adventurer ring is going to maximum, and the +10% maximum from the Onyx ring is going to minimum. All of my whats.