Is there any reason you’re subtracting 1 from the count in the expressions? If the count of followers/following is 0, then this would result in the -1 you are seeing.
I had a brief look at the demo app, and I believe I’ve found a solution for your issue.
On sign up of a new user, ensure to add the Current User to their own Following list as per the screenshot below. This will ensure that the initial following/followers count is 0 and not -1. You will need to ensure the following/followers expressions include the subtraction of 1, as it did in your original screenshots.
I literally just went through this issue this morning in order to debug a similar issue on my app. My problem (that took me absolute ages to figure out) is that I had set up my privacy rules where other users did not have access to the count. If you have privacy rules, make sure the count fields are available to other users.