whenever i go to straighten my neck out by adjusting the truss rod......it seems to slip 1/8 of a turn or so on the first turn. after that it feels normal. i've never turned it more than a 1/4 so i don't think i'm turing it to much????? it feels scary everytime i do it ha hahaha. also, my neck seems to return to it's original position after i striaghten it out after a week or so.....i assumed it was just from living up north but...... why is it slipping?