The 2 vs 3 might be reducing how much you’re torquing the string. This might be the L/R flight issue. On lighter bows especially it’s easier to grab the string and essentially twist it a bit out of its normal alignment, if that makes sense. If you’re doing that, it’ll be less pronounced using 2U So you’ll see less effect or even maybe eliminate it.
recurves especially, but longbow as well, I know the tiller can be affected by the shooter, but a bow tillered for split and shot how it’s designed will be quieter than shot 3U. Bows tillered 3U and shot 3U are better for noise, but still louder than split. Heeling a recurve and high wristing a longbow that aren’t inherently designed that way will mess up tuning, noise, and flight.
if you’re consistent in how you shoot, all is generally fine but it’s eye opening how the bows shoot when shot how they’re designed.