In between not-so-regular gigs these days my 12 year old American Stingray is on a wall hanger, inside a house with minimal temperature changes. After an initial adjustment a while ago, which seemed OK, I picked up the bass which fouled on frets 1 to 5 in particular. I increased the relief only jusy enough to clear the problem and all seemed well. Now, a few months later, the action is too high at 12 fret and you can see the relief bend looking down the neck. OK I can adjust again but I am unsure why this has happened again. I don't really want to get into a cycle of increase/decrease relief and everything I read says hanging by the neck is not a problem. I have checked the neck/body join etc, no sign ofa problem. Any advice appreciated.