The ImageAPI Optimize WebP module generates .webp derivatives for a given non-webp source image. Stage File Proxy attempts to fetch the non-existant .webp source file, instead of the .jpg (or other) source.
The ImageAPI Optimize WebP module appends the .webp extension to the original filename, e.g. imagename.jpg.webp, this differs from the webp project → for which I have linked the related issue.
Patch to follow.
Fixed
1.0
Code
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.
In latest version 2.0.2 for Drupal 10, this patch/fix did not work properly anymore.
Hereby a rerolled patch which should apply to 2.0.2 and fix the issue:
https://www.drupal.org/files/issues/2023-06-09/webp-support-3171559-29_0.patch →
Trying again to add the patch for version 3.1.x