there's lot of reasons. sometimes products that they used to use to manufacture it may have gone out of production, so they had to substitute it. sometimes they have to changed chemicals due to the plastic bottle. sometimes things break down over time and change. chemicals included. so if you had a bottle of OS that was Brand New from 1980, and a bottle that's brand new form yesterday, there's a chance something in it has broken down over 20+ years so its possible that it's changed in the bottle. Unless you own a DeLorean with a Flux Capacitor in it, you'll never be able to compare them. Its also possible that they found an ingredient broke down over time and then changed it to remedy that to help shelf stability.
i'm sure that some, or all of these reasons are part of why it smells different. But... it still smells good. It's just my engineer brain doing the math of why companies I've worked for changed components in any product.
i'm sure that some, or all of these reasons are part of why it smells different. But... it still smells good. It's just my engineer brain doing the math of why companies I've worked for changed components in any product.