Yes, Chase explicitly says that the AU cards will be reported: Chase provides account information to the credit reporting agencies for all account users. This information could impact an authorized user’s credit score. When you tell us to add a user to your account, you’re confirming that you have a relationship with the person or people whose name(s), address(es), and date(s) of birth you’ve told us, that all their information is correct, and that you have their consent to add them. .
Okay, I didn't bother to read all the documentation, thus I wasn't aware that adding my 20-year son as an authorized user would impact his credit, I didn't even think he had any credit to begin with. However, Discover already gave him a credit card and his mother co-signed on his current car loan. So he was already establishing credit
My son has Credit Karma on his phone, and today he told me someone had started a new Chase credit card account under his name. I explained I had recently added him as an authorized user on a United card to get 5k miles. But, I also wanted to give him a Visa card for his impending trip abroad with his girlfriend. They have not yet decided if they are going to the Netherlands, Brazil or Japan. But, I assured him that his Discover card would not get him far in any of those countries, and a Visa card would be his best bet for a credit card (he has a Chase debit card for his checking account). He wasn't too impressed as he pointed to the app on his iPhone.
His credit score had dropped 68 points once the AU card was opened in his name. He also assumed it was fraudulent and had already notifed Credit Karma that he had not opened that account. A major point of concern was that it showed an $1100 balance - a result of my recent purchases - which surprised me. I understood that I was on the hook for paying the card, not him. So, I don't understand why the balance of activity on MY CARD showed up on his profile.
Anyways, I assured him the balance seen on his credit report was only temporary and by giving him a card as an AU, it would eventually help increase his credit rating over time. He didn't seem too impressed, and it was awkward. But, I do think I did the right think by getting him his own Visa card as a backup when he is in a unfamiliar, foreign nation. Oh, and I forgot to give him the actual card today. It only has a $1000 limit, thankfully.
So, I hope my experience might help others avoid a surprise, when adding a family member as an AU.