If snow falls onto grass, then there will be snow and grass in the same place. Totally normal. However, if you place a lectern (or possibly other semi-transparent blocks) on the snow, the snow disappears, but the grass remains, and you have grass and a lectern in the same place. You can't break the grass, only the lectern. If you break the lectern and then place it, the grass disappears. I couldn't find an issue like this, but if there is I'm sorry. I'm still not very good at searching for tickets.