I've put together a nice jazz bass with DiMarzio pickups and an All Parts custom P bass neck. It's my go to bass for jazz, when it's inconvenient to bring my upright. The All Parts fretless neck seems to be of very good quality, except with one issue. When I received the neck, as usual, I lightly dressed it, and then polished it with micro mesh, until it was a smooth as glass. It now plays like a dream, but it seems that every few weeks, if I run my finger along the ebony fingerboard, I can feel the damn lines, which I assume are some type of plastic binding inserted by All Parts into fret slots. Although it doesn't seem to affect the sound, I find this aggravating, and I've had to re-polish the fingerboard at least 3 times, only to have it happen again. I really dislike the lines, but this was a used custom made neck of better than average quality that happened to have the have the lines, so I went with it. Is this being caused by normal changes in the ebony with weather, etc. pushing the plastic lines up? Should I just keeping polishing until this finally decides to subside, or is it probably futile and a waste of time trying to get it absolutely smooth? Thanks!