I too have never had an issue with a battery and I've been shooting Nikon since 2009. I've never checked dates either until this discussion.Does anyone know how old a battery should be when new? I recently bought an "new" EN-EL-C battery dated 2022. It's fine. i never thought to look at the date until reading this discussion. I also have some older batteries dated 2016 that still work fine. Is it possible there was just a bad batch being sold?
Yes, defective products get manufactured. Defective products get shipped. That's why you're given a warranty on new products. Hopefully what you get works fine. If not, you contact the retailer or company and have it replaced. As far as I can see, there's nothing nefarious going on.