I had to laugh at myself on this one. When you said "Collar Error," I thought the retaining collar on the coin press! But you are right! Lincoln's coat collar has what may be a die break, definitely has at least a die crack. Better pictures will help us figure out what's going on.
"Shine, shine, a Roosevelt dime All the way to Baltimore and running out of time" - Tom Waits 'Clap Hands'