I finally fixed a weird issue i’ve had on the ESPHome builder in Home Assistant for YEARS… I couldn’t download firmware from the web UI. The logs would just show a HTTP 400 error with “Missing argument configuration”.
Turns out it was some odd Cloudflare cache interaction where it was dropping query string values - caching was set to “ignore query string” - but this wasn’t breaking anything else in the platform. Just this one specific thing.
Then again, recently I’d noticed a lot of the icons were broken and that came good instantly as well, so it seems they’re not returning cache-friendly headers which make things gross.