When a file is uploaded through the WYSIWYG using this plugin, it is stored as a "Temporary" file, not "Permanent". So it will be deleted by Drupal when cleaning the temporary file on cron run.
We can clearly see the "Temporary" state of the uploaded files in the "Files" tab of the Content section of the administration.
The most convenient solution would be to add a file usage for the uploaded file, so it could be linked to the content, and therefore be cleaned up automatically if the content is deleted. A file with a file usage is always marked as permanent (@see src/FileUsage/FileUsageBase.php).
But if it's difficult to link a file to an entity through the WYSIWYG interface, at least use $file->setPermanent() in the upload form submit.
Fixed
1.0
Code
Not all content is available!
It's likely this issue predates Contrib.social: some issue and comment data are missing.
Fixed in 1.x and cherry picked in 2.x.
File usage is tracked for nodes by default so files uploaded in webforms or custom forms should be tracked differently.
Thank you all for your work on this one!
Sorry for the huge delay :/
Automatically closed - issue fixed for 2 weeks with no activity.