This is normal. The second entry in the meta table starts with an underscore with a value of the fields key. This is how ACF knows what kind of field it is and what value to return for functions like the_field() and get_field(). The post_id value is not random, that’s the post ID. Everything is a post, if you upload images or files while working on a post, those get the IDs between the post IDs that you see. There are a lot of things that go into the post table, custom post types, menu items, attachments, they all get a post_id.
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