I experienced the same thing actually. It was kinda like give someone that rode fixed (not much knowledge of gears) for the longest a complete bike with this group set. Took me like 2 or 3 times (was seeing changing to the front small cog needed 2 presses too) to have heard of trim. Then it all made sense

Did a few short rides, but did a little bit of a ride today and was getting rub on large chain ring and any of the 3 smallest cogs and knew 100% something was wrong. Finally looked these up. There are 4 settings. I guess the guy did set it up correctly after all.

It depends too on the pressure you give it. Large ring trimmed out and just a tap on downshift and it won't switch. But if you press it all the way and hold it for a split second it will shift. Some amazing engineering to be honest. I can only imagine what kind of other cool stuff is out there.