Hi Castaban,
I posted a while back how crappy my harmony works compared to the old 880. I even bought an IR repeater hoping that might help but it is still crappy.
Same issue in that the emitter seems to be very weak or too focused?
I called support and they offered no real help. One cool thing I did learn is that you can use a camera view finder to "See" the IR emitters when they send.
From that I learned there are two. One on each side of center.
I have best results when pointing at the same vertical level but not slightly off center left to right.

I miss my 880 dearly!

Good luck and pleas do post if you get resolution somehow.