The Hollywood Reporter did a piece on creators rights in an age of movie adaptations, and while the piece itself is worth a read, this bit really stood out to me.

Credit can be so important that it can even lead to surprising behavior. THR learned of an instance in which the co-creator of an A-list DC character secretly maneuvered behind-the-scenes to have themselves listed as the sole creator on paper, with regard to merchandise or adaptations, cutting their partner out of payments. According to a knowledgeable source, the other co-creator only learned of this maneuvering years later when a Warner Bros. theatrical employee noticed the discrepancy ahead of the release of a movie featuring the character. (The wronged co-creator now receives payments, but is said to not be on friendly terms with their former collaborator.)
I'm wondering who this could be. Given most of DC's big name characters were created in the Golden and Silver ages, most of those creators are already dead. So if it's a relatively recent big name character who has appeared on film within the last few years (or is scheduled to), it's a fairly narrow list.

- Harley Quinn (Paul Dini and Bruce Timm)

- Cyborg (Marv Wolfman and George Perez)

- Helena Bertinelli (Paul Levitz and Joe Stanton)

- Cassandra Cain (Kelly Puckett and Damion Scott)

- Black Mask (Doug Moench and Tom Mandrake)