I can't say that it's official, but Chase has blocked my last 3 attempts at cards for reasons like "Insufficient credit history" and "Too much revolving credit." I've had my main card for 13 years now (since I was 16) and I have NO revolving credit... just things on my bill that I pay off every month. My wife had her last 2 blocked from Chase for similar reasons. We both have credit scores over > 780 and AmEx and Discover have no problem issuing us both large lines of credit recently.

My only guess is that we have churned through a lot of Chase cards in the past year (UA, CO, BA, Chase Freedom) and use them for Mint purchases. At least we can still do debit cards from them that have mileage bonuses