Pre-assigned break out rooms with titles and no participants

Hello, 

I wanted to allocate people randomly in 4 break out rooms while being on a meeting. Because I wanted to give titles to those 4 rooms and save a bit of time, I decided to pre-assign the break out rooms in the settings before opening the meeting.

So I clicked on 'pre-assign' rooms and I created 4 rooms with their names without adding participants. While in meeting, I pressed the button to allocate people randomly but the break out rooms with their titles didn't appear.  

Has anyone noticed this before? Does this mean that we actually can't pre-assign break out rooms without adding participants?

Thank you!