Thanks for the info.
I think I have figured out the issue.
because you are using a select field to manually set the taxonomy, ACF does not recognize this selected value in the JS.
Then, when you make any change to a taxonomy, ACF’s JS loads up all the selected taxonomy terms and does it’s AJAX request to find metaboxes based on the new location rule data.
ACF does not recognize your select field as a taxonomy term, so it doesn’t include it in the AJAX request. That is why ACF deos not return the correct field groups and your origional group disappears.
To solve this, please change your custom select field to a taxonomy field so that ACF can recognize it!
Hope that helps.
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