Custom folder structure fails randomly!

[hesamzakerirad]

A bit context
I have been using Spatie Media Library on a production system for over 2 years now, and it's been working flawlessly. I changed the folder structure from the beginning to meet the system's needs.
This is my folder structure:

- media
  - product (model_name)
    + 1
      - thumbnail (collection_name)
        - conversions 
      - album
        - conversions (collection_name)

    - 2
    - 3
    - 4
    - ...

The problem
Recently I've been getting this error:
ftp_mkdir(): can't create directory: file exists
and it's been happening randomly for the last couple of weeks. (for some products, it's fine and for some isn't.)

I've checked, and it seems that the CustomPathGenerator that has been working with no problem, suddenly creates nested folders for no apparent reason.

- media
  - product (model_name)
    + 1
      - thumbnail (collection_name)
        - conversions 
      - album
        - conversions (collection_name)

    - 2
    - 3
    - 4
    - ...
    - product (model_name)  // <-------------------- PROBLEM!

This is the CustomPathGenerator class that I created 2 years ago:

class CustomPathGenerator implements PathGenerator
{
    /*
     * Get the name and id for the given object.
     */
    public function getParent($object): string
    {
        return strtolower(class_basename($object)) . '/' . $object->id . '/';
    }

    /*
     * Get the path for the given media, relative to the root storage path.
     */
    public function getPath(Media $media): string
    {
        return $this->getParent($media->model) . $media->collection_name . '/';
    }

    /*
     * Get the path for conversions of the given media, relative to the root storage path.
     */
    public function getPathForConversions(Media $media): string
    {
        return $this->getParent($media->model) . 'conversions/' . $media->collection_name . '/';
    }

    /*
     * Get the path for responsive images of the given media, relative to the root storage path.
     */
    public function getPathForResponsiveImages(Media $media): string
    {
        return $this->getParent($media->model) . 'responsive-images/' . $media->collection_name . '/';
    }

    /*
     * Get a unique base path for the given media.
     */
    protected function getBasePath(Media $media): string
    {
        $prefix = config('media-library.prefix', '');

        if ($prefix !== '') {
            return $prefix . '/' . $media->getKey();
        }

        return $media->getKey();
    }

I think the reason that this error (ftp_mkdir(): can't create directory: file exists ) happens is because of the duplicate folder created somewhere.

I would REALLY appreciate it if you can shine some light on this or share your own experience regarding this.