I did some testing with the plugin files and aparently its this condition in ‘everything_fields.php’ controller the culprit:
if( !empty($screen))
{
return $form_fields;
}
Removing it would solve the show fields problem on upload media but it would cause them to be duplicated in attachment edit page, so I guessed that was the reason for the condition.
Changing it to:
if( !empty($screen) && $screen->id == 'attachment' )
{
return $form_fields;
}
Seems to have done the trick, testing a lot and so far no more of that problem.
I’m just not sure how good/bad this solution is since i can’t even get how the get_current_screen function works or how to debug a plugin’ properly.