Yeah. I heard about that. It seems Pulp magazine had a hero called Black Bat, so DC can't use that name.
Although I think they could still use something like Shadow Bat (I don't think there is a hero with that name) or similar, right?
However, Outsiders seems to imply Cassandra won't use an alias with Bat in the name, since she deserves more than an extension of Bruce's creation (at least, it is also implied Orphan won't last).