The only voter mandate was to align California DST transition in law with federal law (because of the Supremacy Clause, this was already reflected in practice, as federal law superceded state law anyway); the ballot measure allowed the legislature to make further changes as long as federal law allowed, but did not direct any such changes, and it was very clear when we voted on it that we weren’t voting for any specific changes.

So, no, there was no voter mandate that was ignored. The legislature asked for some cleanup and discretionary authority, and the voters said yes. That's it.