Cane mint tasting dull (need advice)

So recently I’ve noticed that my cane mint doesn’t have that minty “sting” when I smoke it. However my buddy’s hookah smokes it fine. I’ve tested it by making my bowl and smoking it, then moving the bowl to his stem and it smokes much better on his just to make sure that I wasn’t messing the bowl up. His immediately has sharper mint taste, the whole shebang.

Any advice as to what’s wrong with mine? I’ve seasoned my stem with only cane mint but it’s a little old. Wondering if the taste will dull over time in old stems or any insight in general as to getting it to smoke better.