This is a photo of the one I mentioned. It too had the dark area around the checks. Hard to make out in the photo, but there are a number of them. I let this stave sit around for years, partly because of the checks, and partly because the whole stave was a mess. scared me. Very thin rings, high percentage of early growth within the rings, reflex on top deflex on bottom. It has held together in spite of all that. Lot's of bending and flexing during tillering and no issue with the checks. Everything else...yes, issues...but not the checks.