yeah, unfortunately its just ebony doing what it does. all wood does it to a certain degree but ebony does seem particularly prone to excessive shrinkage
now we seem to be getting different weather patterns you will spot it more and more, most of our US friends are a lot more used to dealing with seasonal set-up issues than we are over here
have it looked at professionally. try to pick the point in the year where its at its worst, usually when humidity is lowest. if you get them filed back and redressed at the worst time of year then generally they don't need doing again
