The taxonomy (categories, tags, series) pages on Fluxposure were timing out. This was also obseved in the proxy logs, with many H12 timeout errors appearing.
After investigation, this was caused by the category links in the site theme somehow being configured to not have traling slashes. This would cause a redirect to remove the slash if one was present; i.e. https://www.adrianflux.co.uk/blog/tag/3d-printing/ would be redirected to https://www.adrianflux.co.uk/blog/tag/3d-printing. Since all the URLs going through the proxy get normalized to add a traling slash (at edge), this was causing an infinite redirtect loop between the blog site and Cloudflare edge.
A high-priority function was added to the functions.php in the sites theme to basically always use a traling slash. This in effect disables the “remove slash” redirect and the subsequent redirect loop after.
It was subsequently noted that there were some infinite redirects that had been added to Yoast also. For example:
`4x4` -> `/blog/4x4`
Since the site is proxied at /blog/ this had the effect of causing an infinite loop also. Each category and series was tested and the appropriate redirects removed. These were probably added in as the result of an automatic action somewhere when a category changed it’s slug perhaps.