E.g. this ant insecticide was recently on sale for $15.99 during Oct 7 & 8 and yet that lower price was invisible to camelcamelcamel: https://camelcamelcamel.com/Miller-8150120-24-Ounce-Disconti...

Those blind spots happen for many items and my reverse-engineering guess is that they simply don't have the compute infrastructure to track/scrape all the millions of ASINs. Therefore, many price changes are completely missed. I'm sure they're doing the best they can but it seems like the only 100% accurate way to track price change history is for Amazon.com itself to offer it. Amazon likes to say they're "customer-oriented" and providing an official price history dashboard would help shoppers.