“Witness On Ticket... No Witness”

Hi. I'm looking at defending a failure to yield the right-of-way charge. On the ticket, the officer ticked the "witness" box to indicate - I guess - he got a witness statement, contact information or... something. Well, post-discovery, there's nothing about a witness. Is this a defence angle in that evidence the officer claimed to have the justify the charge doesn't exist and was mistakingly identified on the ticket?