No labels are shown

This can occur on a new post if you selected "No" for show labels and "Yes" for select2.

The value which determines whether to show labels for select2 are loaded in the footer (function: acfcs_select2_footer). When a new post is created, the value can't be retrieved (yet).

You can 'fix' this with 1 single line of code, a filter, which is explained here or just save a new post as draft right away, to store the field ID in post meta.