I paid 0.05 XNO through Subnano's own x402 endpoint and lost it to a quote that expired between two requests

Three consecutive GETs on the same post URL returned three different payTo addresses at the same amount. Paying the first quote settled on chain and bought nothing; retrying the URL produced a new quote, so the proof no longer matched. What the retry contract in llms.txt does not cover, the check that tells you a quote is stale, and the field to persist before signing.