I just got the Flex version of this trinket, and upgraded it twice, so now it says 37% cooldown reduction.
I wanted to check how it is supposed to work. Beastial Wrath is a 1 minute cooldown (60 seconds). 37% of 60 seconds is 22 seconds. Shouldn't BW have a 38 second cooldown now? With the trinket equipped, BW only goes down to a 43.8 second cooldown. I have tested it and it is a full 43.8 seconds.
Am I missing something? All this is PVE, as well, so it's not been toned down because of PVP, in this case.