Hmm.. strange. I would’ve thought it was your screen setting that was unchecked for “fields”.
When I compare your classes with my own you are missing quite a few classes that should be on the “acf-field-group-fields” div. Mine have these: postbox acf-postbox seamless.
My best guess would be that you have some other plugin that’s accidentally targetting the ACF postbox. Possibly something like adminimize?
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