I replace the 5 day hops for fresh ones, generally I use leaf hops as they don't disintegrate and get through the material I use. As for the grassy note I have no idea, others on here will do though
Was going to say your local micro brewery too, and take some of your beer along as well, it helps grease the wheels of industry and they can give valuable feedback
Grassy notes are supposed to appear if you dry hop for too long, around 10 days or so, I switched to a 5 day dry hop, replacing the hops for another 5 days
Works for me
I did something similar a while ago and short answer was no it didn't, I will have changed the flavour a little but it was still poor tasting beer, cheap mind you just poor, was glad to see the last of it drunk