A court may well consider that becoming a wholly owned subsidiary would violate a license, despite being a distinct legal entity[1][2]. Especially when it's just an implied license with no actual agreed definition on both sides.
[1] Which is similar to what we're seeing with ARM vs Qualcomm and it should be interesting to see how that shakes out.
[2] Mojang into Microsoft sounds like "forward triangular merger" on this page: https://www.faegredrinker.com/en/insights/publications/2003/...