Problem with Zoom Breakout Rooms

Hello all, I am having problems with using zoom breakout rooms. I am assigning meeting participants manually to the one of the two rooms we normally create, to give on average 8 to 12 participants in each room. There is an issue that some participants are are not in the room assigned, as there is no green dot to the left of their name. What do I do in this case ? Do I wait or try again to manually assign them ? 

The second issue I have is when late-comers arrive to join the Zoom meeting. I had a case when I manually assigned a late-comer to one of the breakout rooms. The person was not immediately assigned. In fact it took 2 to 3 minutes for this to happen. A frustratingly long delay if you are the Zoom host. If anyone in the community could guide me it would be appreciated.  Thank you.    Donald