Bottom line to visiting dealerships, there are some real good ones that will simply look the other way on aftermarket stuff. If this is you your very lucky, on the other hand there are also some dealerships where there are some real assholes. If yours is one of those unbolt, unplug, remove anything aftermarket and save yourself some grief.
I can tell you first hand on my 2013 I was having some problems with DEF quality and limp mode warnings under warranty. I went into my local Chevy dealer and forgot to remove my Edge CTS and was told my warranty was going to be invalidated because of using an aftermarket tuning device.
I then had to go thru hell proving to them that the Insight CTS WAS NOT A PROGRAMMER but a monitor and had nothing to do with the problem and that my truck was 100% untouched.
Anyway, now when I go to the dealership with my 2019 I remove my Derringer, Idash and pedal monster. I never want that hassle again. If your going in for an emission/code issue I can see where the
S&B filters MAP Spacer could give them a good excuse to say you modified your emissions and created a problem though we all know that's dealer bullshit.
Be safe and save yourself problems, it's easy to remove, just do it and put it back on after you get your truck back. Or another option spend the money on a couple of spare sensors forget the spacer and never worry about the dealer issues.