Essence Reaver Only Granting 10% bonus CDR

I had Quinn on ARAM and I had an IE and the ER for 40% crit total. ER reads that it gives 10% CDR as a unique passive. In ADDITION you gain up to 20% MORE CDR from crit, maxing at 20% bonus CDR at 30% crit. So with 30% or more crit chance and the ER you should have 30% CDR.

But with 40% crit and the ER I had 20% CDR. So I was either only gaining 10% bonus CDR from crit or the passive itself was not active.