Ken, are you, or have you ever been, a member of any underground, subversive groups? I had to play on your "suspicious" background.
Seriously now. You weren't the OP I was referring to, but the originator of this thread. I re-read your post carefully and I'm at a loss to explain why your second coat failed. The only questions I would ask is a)was a second coat specified b)was 72 hours beyond the watch period for rain, and c)was it a latex product? The implication of your words is that you followed the instructions carefully, but what you describe sounds like applying a second coat over a one coat product, it didn't penetrate and cure properly. Firstly, no products are what they were 15 years ago, IMO, they're worse. The government is forcing VOC based reformulations and it's having a negative impact. I really don't think the paint companies know what their products will do or how they will perform. Secondly, since Behr has worked well for you generally, I would stick with it. You've had a satisfactory 16 year experience with it. Regardless of all that's said with regard to Behr, the fact that it is working for you in your case is all that matters. I would contact Behr at their hotline and ask them what they think happened and what to do to correct. They may have an answer for you. Before you call, get the batch numbers off the can/lid. They may ask, and if they don't, ask them if they've had notice of any bad batches. Welcome to the everyday world of the paint contractor. Good Luck.