Followers: The first list is of people who follow you. It apparently does not have a limit. It can't be changed unless other users follow/unfollow you.
Following: The second list is of users you are following (you see their activity in your feed), which does have a limit. It can be reduced by unfollowing some users.
Follower = a person who follows you, who clicked 'follow' button on your profile, your follower. Following = a person whom you follow, you're his/her follower, you clicked 'follow' button on his/her profile.
The two lists followers and following tells you two things your followers and to whom you follow .So, it can't have a limit .Its a limitless.If you still having troubles related to this send a feedback to the app.