Casting Fishing While moving Slows You Down

Since i start playing skyblock i level up all the skills except from fishing, i decided to starts de quest and fish when i realise theres a bug when i use my fishing rod that i cant see the string, i know its a bug couse i see everyone using his grappling hook or fishing but i cant i would like to know how to solve this, this is what i see when i right click nothing, in theory im doing the same as this other player