I don't know how the contracts were actually written, but I suspect it would legally classify as a "breach of condition." This kind of breach entitles the innocent party (i.e., Van Halen) to terminate the contract. Of course, the contract itself can override this interpretation as it sees fit.

However, as noted by others, this is rather moot: someone who didn't notice this line in the contract probably didn't notice all the other (more serious!) issues.