just upgraded ACF after not using the site for many many months. I went to add some new repeater sub-fields to a repeater field and they have all disappeared. Anyone else have this issue? Anyone know what happened and how to fix?
I have not seen this.
I would first suspect a browser JS caching issue. Clear your browser cache.
Next I would suspect a JS file was corrupted during the update. Delete ACF and reinstall, this is safe to do and no data should be lost as long as you did not save any changes to existing groups.