My sinew and hide glue backed osage was a constant source of heart attacks for the first two years I shot it. Every time I picked it up it would make another cacophony of cracking and snapping sounds. Ultimately it developed longitudinal cracks from fades to tips as the sinew continued to shrink and add tension to the back. The bow started with a little crown and now has, for lack of a better term, anti-crown. The back of the bow is not literally cupped from the sinew and hideglue. It has reached a static condition now and is silent and deadly, much like the after effects of my famous antelope chili.
Just keep watching the back, and if you have a spot that feels a little rough, run a cotton ball across it to see if it snags. The cotton fibers that snag will help you find any spot where a fatal crack may be developing.