Fret leveling issue
 

The neck is unstrung and i am using a fret rocker to check each fret. But once i get above the 4th fret every fret rocks. This doesn't make sense to me. Any ideas ?4

Neck has a back bow? Level fretboard then check frets for level-ness.

Check the truss rod first, it may have been cranked down too hard. Figure out what's causing the back bow of the neck.

Of course! I thought the neck was straight but I should have double checked.

Thnks guys

It's unstrung. With no tension, many necks have a back bow. That is why I check for high and low frets while the guitar is under tension.