Terrain changes in non-erg workout mode

Hi all, apologies if this has been answered elsewhere.

I often make custom workouts on Zwift for indoor entertainment but want to ride it non-erg mode so I can ride to my RPE. When I do a workout in non-erg mode, does the trainer still respect the terrain and make resistance changes accordingly (ie do I need to make gear changes to maintain my target power, particularly in hilly courses)? Thanks.