I’ve had similar results in similar conditions. What’s odd though is this: when the chain got noisy during a gritty ride, I blasted it off with clean water (not drink mix!) from a water bottle, and it got quiet and stayed quiet for the rest of the ride. Another time I had similar experience with dust - for the final 20 miles of a long ride, the chain was really noisy. I didn’t have any extra water so I just lived with it. When I got home, I blew off the chain with an air compressor and it got silent again. So I think sometimes dust and grit sticks to the wax. The wax is still there, but there’s stuff on top of it. All that said … I’m trying the Silca Synergetic stuff now. so far so good.