Relative line number not always displayed correctly

Sometimes (from what I saw it's usually on functions and for loops but not all of them) the relative line number is displayed incorrectly:

• There is an offset between the line we are on and the 0
• The 0/real line number is not displayed correctly

This happens kind of randomly and I haven't find a way to reproduce it or understand precisely what's causing this (but if it happens on a line I can modify the line or some lines below and it will stay for that line).