The fact he was leaking documents and got caught tells me this was not a one of event.
The article below does not appear to be posted on FR.
It talks about how Comey discussed private conversations with Trump with another friend of Comey’s, Benjamin Wittes, editor-in-chief of the blog Lawfare and former editorial writer for the Washington Post.
Public Accounts by Friends Show James Comey Leaked While FBI Director
http://www.breitbart.com/big-government/2017/06/22/public-accounts-by-friends-show-james-comey-leaked-while-fbi-director/