I am starting Hybrid Mode Deployment for Exchange Online and I got to the point where I added Exchange Online to my EMC. After doing that, I went to Recipient Configuration->Mailbox and found a user in the mailbox that is also on the On-Premise server. I'm a bit confused because I haven't migrated anyone yet.
My questions are: 1. will routing be messed up if he's in two places? 2. what happens when I actually want to migrate him?