u/live-laugh-love-you

I've been drinking the 6 pack bottles of Diet Coke nearly all my life. Recently, I noticed the neck of the bottles, especially the area near the caps have a weird smell, the only comparable smell I can think of is earwax. Tried a 20 oz bottle from the gas station today and it has the weird smell too! Anyone else notice this? I'm in central North Carolina if that helps!