Just an update for the OP, but I was able to reverse this issue on my main user account by deleting the settings for my ACF meta box positions in the database under wp_usermeta.meta-box-order_acf-field-group.
Not sure why it happened in the first place, but at least I know how to reverse it now.
Thanks to Mike from support!
John,
Unfortunately, the arrows you’re mentioning aren’t actually there for the “add new field group” meta box in the ACF admin, at least with my issue. (They are there on the page/post editing side of things though) Also notable to my issue is that the other meta boxes are draggable from the main content area to the sidebar content area – except for the “add new field group” meta box which appears locked in place.
I also just tested this again, and it appears creating a new user account fixes the issue and the “add new field group” meta box is once again positioned in the main content column/area. So it appears this is somehow tied to the user account, but not sure how/why.
Were you ever able to figure this issue out? I’ve ran into the same problem.
Using ACF 5.9.5 and WordPress 5.7.1.
Here’s a screenshot of the issue:
