No added value
Can you relate to or have you ever experienced a similar "conversation":
A: I can see nothing demonstrable in the current sprint task list.
B: I beg your pardon? It's the second to last sprint before the release and there's a ton of work still not finished.
Yes, there are people who, for any reason, dislike doing demos (I am a member of the club myself). And certainly all projects have sprints in which the majority of work was solely refactoring, bug fixing, testing, and so on.
Although, claiming there is nothing to showcase while the release date is approaching fast and the MVP is still incomplete clearly isn't right.