Water in Naish Makani Vario Psddle

When I get out of the water I rinse both halve of the paddle shaft and let dry. However, there is always water left in the top of the shaft near the handle that never drains. I don't think this is normal. I poked a small stick down the shaft and there appears to be a bung about 10 cm down from the handle. It seems water is leaking in behind the bung plug and staying there. Yesterday when I put the shafts back together then took them apart without getting them wet the water released either from behind the bung and poured out. I thought about pouring a bit of epoxy down the shaft to seal the leak. Is this a good idea??
90 Mile