Oh, I wouldn't reach that conclusion just yet because I think the headlight delay can be adjusted. Exactly how I don't recall.
I just read about the headlight auto shut off feature in my owners manual. It states that it can take 3 minutes before the lights auto shut off, or immediately when you open the door. I tried it and sure enough it took 3 minutes to shut off. Previously it would shut off after only a few seconds. That's why I was concerned. I must have inadvertently changed the setting for that feature somehow. How? I haven't got a clue. I'm just glad that it still works, albeit slower than when I first got my car. Thanks to everyone for your help.