page template with custom post type loop case page duplication

I think this issue is connected to has_archive set to false in your code. So you need to set ‘has_archive’ to true in register_post_type()
‘has_archive’ => true,
And then Please flush permalinks after you update that property.
I believe it should help.
Also, you might need to create a custom template for archive of this CPT, check this section of the codex.