(I don't have the photo proof yet, but I can assure you that it's true)
Warning! This bug does not always happen, but when there is it is noticed that it is a bizarre thing.
1. Press shift+s (you must go slow)
2. When you stop you will notice (in f5) that you will be in the air
The bug:you are in the air even if you're beyond the hitbox
What is the bug here exactly? From your report it is not quite clear what the issue is.