Has anyone experienced this? I’m moving my character around in the viewport and suddenly for no reason my model zooms in… I noticed this happening most with high density models… The only way around it is to wait a few seconds after every viewport change, which slows down my productivity by a lot… anyone experienced this or knows a way to fix it? thx
Turn off Preferences>Interface>Rightclick Navigation and save the configuration (Shift+Ctrl+i).
sweet, thanks you! 
I just checked again… It’s definitely gotten better… but when i zoom in it still snaps to a closer zoom than expected… seems like zbrush lags in determining if i’m holding the alt key or not…
I think perhaps you are holding the Alt key down longer than necessary. You can let it up the moment you have clicked on the canvas.