Just went and tested the new duo and saw my equipped colas were down to 7 afterwards, so I went to get another stack to put on top of it to refill to 12. I use a PS3 controller when I play, so I pressed square on the stack in my inventory and normally that would immediately give me a box with a counter that I could press up or down on to choose the amount of colas I want to move, but instead it just grabbed the whole stack. I thought it was a new feature first but then I realised it also meant I wouldn't be able to split stacks of anything else such as exos, matter enhancers etc. and realised that has to be a bug.
I didn't catch this until everything went live today. I sent a message on Twitter, and they said they will look into this. UPDATE: https://dgcissuetracker.com/browse/DC-1771 They tracked it, and shows fixed internally now.