Confused about 6th day workout: FB 30 Day Challenge

I just started the 30 Day Challenge and I am so excited! I am a bit confused, though. Traditionally, FB programs give five workout days with one optional recovery workout on the sixth day. However, when I added the 30-day challenge to my calendar, I noticed that the sixth workout each week is marked required, not optional (see screenshot). When I read the program guide, the language says those workouts are optional, though: "Though this monthly calendar shows that you will be working out 6/7 days a week, it's important to realize that the sixth day of each week is a very low impact workout that has been strategically picked due to the fact that it is easy on the body, without putting muscles, bones, tendons and ligaments through any excessive stress or strain. The sixth day is completely optional."

Should the sixth workout every week show up as optional instead of required?