I could have sworn I wrote a long answer to this.
Basically, this is just default wagn behavior: autocomplete with card names. Each item in the dropdown is a card, and any of those could, in principle, be a value option (though most of them won't). In some cases, this could actually be useful, because at least you'd know when you had an exact match to an existing card.
If you think it's causing significant confusion or bad impressions, we could limit it to card that have previously been used in value options...
Thanks for reply Ethan, I think in this context it would make sense to limit the suggestions to previously used value options but because the majority of the autocomplete options are just not applicable in this context and it might lead to more standard categorical options/values. I also noticed that I had selected 'NOx emissions' as a value type where really it should have been 'No, just because I entered 'No' then enter and it must have autocomplete to 'NOx emissions' so for me it just makes sense to remove this and therefore reduce the number of possible errors and confusion.
This is a select box now (and more interface improvements are coming)