Is my employer out of compliance with California law?

For background, I work for a company based out of Texas, and I'm employed in California. I had a baby in July, but missed my window to add her during a qualified life event. So I had planned on adding her during open enrollment, which was from October 10 - 25.

I missed that window too. 15 days seemed sketchy to me for open enrollment. I looked and under California Code of Regulations Title 10, § 2699.6139, they needed to have given me an open enrollment window of 30 days.

HR told me that under Section 125 of the IRS Code, the company established an October 25th deadline, so they won't be able to give me favorable, pre-tax treatment under their cafeteria plan.

Basically, I told them that California requires them to give an enrollment window of 30 days, and they said that their IRS deadline has already passed. To me, this sounds like a them problem. Am I correct and should I push this further?

Is it worth it? $200/month for my child's health insurance isn't the end of the world, but I see red thinking about how I'm pretty sure my employer is pressuring me to drop something I have legal standing to pursue.