When i click on a schedule, the unstudied terms only show a fraction. It's only showing the terms that i would study as part of my daily goal. I've had the same issue with the Japanese basic vocabulary list as well.
I can never tell when this is an actual issue and when the pair of vocabulary and grammar schedules working as intended causes confusion
The grammar schedule is meant to slowly introduce new expressions (I think in pairs), which in turn "unlocks" words in the vocabulary schedule. So having 2 unstudied expressions looks normal to me.
You can see the total number of "terms" from here:
I was just a bit curious as to which words I would learn later on in the schedule. The schedules being linked together does make sense, maybe the order i study them in is a bit weird. Though i do wish that i could see all the remaining words in the vocab schedule.
You should be able to click where it says you have things unstudied. It's a list on its own other than your main list. Same goes for terms hidden and on occasion, things that can't be studied. If you also click your main list, you have a filter drop down menu that you can toggle between these lists as well.
The only thing you can't see extra terms ahead is when you have an auto generated schedule that pulls from lists of different topics.