What I’m wondering is: did you maybe edit the theme in such a way that it’s causing what you’re seeing?
The normal behavior of setting an alternate label is that it replaces the regular label when we display the values, which is why I’m suggesting maybe your theme changes are causing this duplication. Also, I’m still curious about how actual values are displayed here: are there values cut off on the right of this screenshot, or something like that? Because I don’t seem to see any values there, which is odd by itself.
Another option that may clear things up, if your site is publicly accessible, you could share a link to an item. It may be easier to tell what’s happening by looking at a complete page.