You are mostly right, except that in addition to the same license, the Share-Alike provision in the OSM license (the ODbL [0]) also enables derivatives to be re-released with "A compatible license."

I am not a lawyer, but I would assume someone at Overture has deemed their license (the CDLAv2 [1]) to be "compatible" with ODbL. (edit: From the link in OP, the OSM-based data is being released with ODbL. I think I'm wrong about license compatibility. Again, not a lawyer.).

[0]: https://opendatacommons.org/licenses/odbl/1-0/ [1]: https://cdla.dev/permissive-2-0/