My skill allows people to ask for information at a day in the future (or the past.) The AMAZON.Date slot seems completely inconsistent in how it will interpret days of the week. For example, sometimes "Monday" will yield the next future Monday, sometimes the more recent past Monday. This is even if I use the exact same utterance. It's totally unworkable.
Here's a suggestion. Past days of the week should require, e.g., "last Monday." Just a straight day of the week with no modifier should always be the closest future named day. It needs to be regimented somehow.