@BayAreaResident - I'd be interested to know what you did about this (if anything) and if you had any success.
My experience today flying MSN-ORD-LGA. I approached both gate agents before the boarding process and when they were not busy, and told them the following (which was true): I got the credit card and was expecting group 2, but got group 3. I called service but they couldn't fix it, but they said to ask the gate agent.
MSN - Agent said he couldn't change the boarding pass, and he'd never had anyone ask to change boarding group before so he wouldn't know where to start, so board when my group is called. A total of 3 people boarded in group 2, so less than 1 minute real-world difference.
ORD - Agent just said to show him the credit card when boarding and then I could board with group 2. I told him I was checking with him first because I (genuinely) didn't want to disrupt the boarding process, and I know that "whip out the card" isn't standard procedure. When he called group 2 I showed the card, thanked him again, and boarded without incident.
Between flights I stopped at the customer service desk in ORD. The supervisor there said that the free bag fee requires purchasing the ticket on the card (I know!) and he didn't know about priority boarding. Someone else there chimed in and said priority boarding does too, and the supervisor said "so there's your answer." I also picked up the official paper credit card application while in ORD and the terms and conditions match the website -- i.e., not required to purchase ticket with card for priority boarding. I also read (and photographed) the fine print on numerous sign advertisements throughout concourses F, C, and B (I had time to kill...) and all signage matched the website.
I can now clearly see why the card T&C basically say "Chase isn't responsible if United doesn't honor this" next to most every benefit. The only other thing I can think of to do is to call Chase with this tact -- United isn't honoring the perks, which is the whole reason I got this card. I know Chase isn't doing anything wrong and the T&C say you're not responsible. But maybe just maybe YOU know somebody at United who can fix this, because I really want to keep this card?
Honestly, I really don't expect to get anywhere. I'll have zone 3 on every remaining United flight and all are on regional jets, so the practical difference is small. I'll just cancel the card before the one year renewal and generally become a disgruntled internet reviewer posting 1-star reviews of the card as many places as I can find to do so.