I have not tasted this beer, but from reading the description, I can venture a guess. When I see "rich malt bill" I think Munich malt, and some Munich malt, especially the darker varieties, can lead to what I call a "vegetal" flavor in beer. After having brewed a couple of all-Munich dunkels and bocks and getting that flavor, I pretty much have given up on them. I use Munich much more sparingly these days.