Laravel's Uploaded File loses properties while passing between methods

In my controller's method I call my service to store images.

MediaService::storeImages($pa, $r->images, $r->main_image);

FileService.php

public static function storeImages($pa, $images, $mainImageName)
{
    dd(1, $mainImage);

    MediaService::addMediaToCollection($pa, $mainImage);
}

public static function addMediaToCollection($model, &$medium, $collection = null)
{
    dd(2, $medium);
}

First dump and die looks like this:

But the second one turns into this, losing its attributes:

I tried adding and removing & to accept the pointer instead of copy but it didn't help.

I know I could create instance of this class and have the image as a variable accessible by all the methods, but its beyond my question, which is - why this occurs and how to stop it?

Thank you.

source https://stackoverflow.com/questions/76794645/laravels-uploaded-file-loses-properties-while-passing-between-methods