Tests performed with both Firefox and Chrome. Although the setting Polish setting is set to Lossy and webp I have also tried using the Lossless setting. Flushing both individual resources and purging the entire cache had no effect.
I’m having a problem with some uris where they simply are not converted to webp and contain no cf-polished header. Removing the query string doesn’t seem to have an effect.
Here is one example of many that works showing the additional headers by polish:
Request URL: https://asite.io/s/pages/home/images/categories.png