This issue is not directly related to Profiler. I'd suggest checking the connection setup by NetworkManager and Spawning order. The Profiler cannot show any connection because from the Game Logic I understood the game tried to spawn a variable that is not listed on the Manager.
I also added in the comments a check on UI buttons because I could set up the Host and Client on the Network Manager inspector and the console issues dissapeared. Please do not hesitate the open another ticket if you could reproduce Profiler issues when the network is set up.