Man... early into growing, I used to wet trim as much of the sugar leaves as I could, getting it as close to bag ready as possible before hanging it up or putting it on strings in a box etc. I figured it saved time and was gentler on the trichomes. But that was where I ran into these sort of issues. It smelled awesome as I was trimming, then a few days later the buds would smell like hay or grass clippings. Even when I was very careful to jar right away and carefully monitor the cure... the smell was always at least diminished.
Then I started thinking about where I live. Colorado. It's super dry here. I needed to make sure the dry time took longer.
So I tried just trimming the big fan leaves, and leaving all the sugar leaves on to hang dry with the bud. Just like that, night and day difference. The sugar leaves trapped so much more terpenes that way, the dry time extended to about 8-10 days, and the smell/taste has always been right on ever since.
So that's the main point imo. You really want to get a dry time of at least 7-10 solid days, before those stems are cracking and ready for jars.
If you live somewhere on the drier side, avoid trimming really any of the sugar leaves, let them hang over the buds, and stick with only the big fan leaves at harvest. Let them hang for at least a week, and even before you put them into cure, they should have good taste/smell that only gets better as you cure.
You should only wet trim if you are worried about it being too humid during dry time, and you expect that leaving the sugar leaves wouldn't let them dry out properly within 2 weeks.
Either way you decide to dry, you never want to go into cure with grass/hay smelling buds hoping that the curing process will bring the magic back. It doesn't work.