that sounds iffy, the movement alone may be reasonable, the encoders on my OT have a little play, but no significant worrying noise, remember it’s not like a potentiometer with finite travel, it’s continuous and free to some extent
those encoders are not surface mounted, i believe they are well hooked up, but the internals of the encoder could have play, as might the knob cap, so a little noise is normal
if it was new it’d be very puzzling unless you’re still just not used to the feel of those particular encoders