https://puzzles.nigelcoldwell.co.uk/seven.htm
The key complication is "once you've opened the door, you may no longer touch a switch." It gets this. There are many examples of it written out on the web. When I give it a variation and say "you can open the door to look at the bulbs and use the switches all you want" and it is absolutely unable to understand this. To a human it's simple: look at the bulbs and flick the switches. It kept giving me answers about using a special lens to examine the bulbs, using something to detect heat. I explained it in many ways and tried several times. I was paying for GPT-4 at the time as well.
I would not consider this thinking. It's unable to make this simple abstraction from its training data. I think 4 looks better than 3 simply because it's got more data, but we're reaching diminishing returns on that, as has been stated.