I think I figured this out.
I added to my DefaultEngine.ini:
[Core.Log]
LogStreaming = Verbose
LogConfig=Verbose
LogProperty=Verbose
Then, right before I get that message, I see that I am trying to load a property from a config file that points to a class that doesn’t exist. I fixed that, and the problem went away.
It seemed that the non-existent class put the config loader into an invalid state, which caused the SUBSEQUENT CDO loaded to be filled out with an invalid property, which obviously can cause all sorts of crashes.
UDN if you have access: https://udn.unrealengine.com/questions/394907/non-existent-class-in-config-causes-subsequent-cdo.html