They are called mind altering drugs for a reason. Because you are actually somewhat aware of your mind being altered and loosening of the restrictions and rules that are created in mind for physical world.
This conscious or unconscious realisation during and after the trip leaves a profound impression on you that everything is about perception.
GPT-5 Thinking (Think Longer) and Opus 4.1 Extended Thinking both get it right.
Maybe this unique problem is somehow a part of synthetic training data? Or maybe it's not and the paper is wrong? Either way, we have models that are much more capable at solving unique problems today.