Mine does too, but it's just been the last couple of days or so. I don't know why it would smell that way, but it's freaking me out. I don't drink coffee or take Melatonin, though I do drink enormous amounts of water daily.

Mine has smelled like pop corn for 5 or 6 years now,Also testing shows red blood cells in urine. Had all kinds of tests found nothing wrong.
Did nor have this in my early 50's now in late 50's this has happened.
I have been on blood pressure medication and lipator for past 5 years to deal with moderate levels of blood pressure increases. Who knows? Maybe its all the plastic and food preservatives we eat now. Supposedly human bodies decompose slower than any equal animal carcass because of all the accumulated molecularly stable food preservatives and plastic by products bound up with the proteins in our bodies.