Inexplicably, approximately every 15 days, directories in the product cache are deleted. For example:pub/media/catalog/product/cache folderDirectories:06fb9c44xxxxxxxxxxxxxxxxxxxxxxx214a0e1acxxxxxxxxxxxxxxxxxxxxxxxxxxxcc90f6xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx364 

inexplicably the cache is being periodically deleted, the scheduled tasks have already been reviewed, and the task for this purpose does not exist. What can be the cause ???