Harpie feather duster, Mystical space typhoon, and other cards effects are not working on field spells (without any protection). This is really frustrating. Is this a Yu-Gi-Oh specific game mode mechanic or is it a bug?
It is likely a bug in a game mode mechanic: I tested destroying field spells in a regular duel, and it does work; which game mode were you using?
Master mode
Again, it works on my end. May I please have a replay of this happening?