I have a functioning D8 site that has recently started displaying odd behaviour. Image styles are no longer generating correctly.
The sample.png used in the image styles config page generates fine (including if I delete the file manually from the image styles dir).
I have recursively set 0775 (dirs) and 0664 (files) to the entire sites/default/files directory, but the error persists. Error log just shows "access denied" - nothing more informative.
Drupal version is 8.1.9.
Any ideas? The site looks pretty lame right now!