I've not had one smell of pop corn, but I have noticed that each cat does tend to have a scent of their own, I will happily cuddle them and take a good sniff at times.
I will also add what is one of the oddest tales I have. Its going back a few years, but I noticed my cat's scent had changed, so feeling rather silly we decided a vet visit would do no harm. They checked him over and while they found nothing really wrong he did need a dental, so he was booked in for that, and as a preliminary they would do blood tests. We got the call the morning he was waiting for surgery, the bloods had shown up he had early signs of kidney disease. it was still fine for him to have the dental work, but it was something we needed to be aware of and discuss with them. That is what I had picked up, his kidneys not working properly had changed his body odour, I had felt stupid going to a vet and saying his scent had changed, but in the end it was more than justified. Having picked it up early, a combination of dental work and diet changes meant his kidneys actually recovered and he lived another few years into his late teens before old age finally took him from us.