I was organizing my cash items when I took out all of my cash effects and then pressed the organize button, which made them stack. I can't unstack them. When I put it back into cash shop, the number (stack of 7 for example) disappears. I then tried to trade it to my mule but trading made me d/c. It's not really a problem but it's just weird.
You can try dropping them 1 by 1 to un-stack them If any of the NX items went missing, please submit a claim at Character Issues so that the GMs can refund you upon confirming the missing NX
When I drop them and pick them up, they rejoin the stack instead of becoming individual. When I pick them up on another char, they come in stacked form. I noticed this is true for smega and weather effects too so I guess any NX that is stacked is unstackable after the fact.