dunno if this will help, but when you trim you effectively put the stick in a different position, so lets say an average flight, you take off and rise up going forward slightly, as you do you gain a bit of lift and so push the stick forward and trim etc etc etc, in the end you have a good forward flight, but in reality your stick is aiming down more than it was but your flying level.
if you try and pull up sharply you will need a huge stick input, maybe not even enough, so you would quickly re trim and pull up again and voila!
I'm trying to simplify whats going on to help you get my drift, in case this is just you trying to get used to it.
do I low flight not too fast and see if anything changes.
after all this someone will come along and say its a problem lol.