Throttle won’t stay in position at low throttle

I have a 2017 SR400 and I’d like to know if anyone else has the same throttle issue I seem to have. We live on a river that has a long no wake section and when going upstream I have a hard time getting the throttle to stay in position where I’m giving it enough gas to go upstream but not so much that I’m throwing off a wake. Often I have to hold my hand on the throttle to keep it in position or I end up going too fast and throwing off a small wake. My dealer and Supra have both said this is a ‘Safety Feature’ which doesn’t make sense to me. Also, I’ve driven many boats and have never run into this before. I would love to hear if this is normal for a Supra or if I have a defective throttle. Thanks!

Same thing on my '89. I always figured it was just some wear in the control assembly and just dealt with it. It can be a pain in long no wake areas but not that big a deal to hold it just off idle.