What I am referring to is the yellow (not max length)/green (max length) indicator does not scale with the length of the underground belts while you are building them. It shows once they're built. this results that if you click/drag underground belts it will default only to the Common length even though at Legendary it can go double that. (yellow belts common distance 5, Legendary 10
This looks like an artifact of when you're selecting Legendary Undergrounds on the menu screen it shows default ranges.
