I've had many folders over the years and the latch on my RadMini 4 is the sloppiest I can remember. The frame cutout seems way bigger than it should be for the latch face (the thin sheet metal cup with the plastic insert) to bridge properly. The cup piece on mine was all bent up from dropping into the slot at an angle, and trying to align it to bridge the slot squarely before tightening the handle was a very fiddly process and it wouldn't always stay put. I ended up adding a relatively thick stainless "washer" under the cup to better bridge the slot and the latch tightening action/feel is now much more consistent.
I haven't isolated any worrisome noises to the joint itself on my Mini, but it's not unusual for folders to creak more than solid frame bikes, usually more so from their long steering stems than their folding joints though.