Very interesting -- thanks for the report!

If it were me I'd retire the shaft and give the blade and grip a new one. I say it because of my experience when I snapped a ZRE medium Power Surge carbon fiber loom in two, right in the middle, and attempted a repair by installing a good fitting cedar plug with thickened epoxy, then wrapping the outside with 4 oz S-glass. The glass failed promptly, so I removed and replaced it with 6 oz S-glass. Same thing. I replaced the shaft with a new one, no more problems. So evidently the shaft of a singe blade canoe paddle is where all the stress is.