I have quite a large field group made for an options page, and when I try to create a clone field, the list of fields to clone is empty. Only a text “The results could not be loaded”
is displayed.
Interestingly, it’s only happening in this one field group. Others are fine and display every available field properly.
Figured it out, was running into PHP max input variables limit. Increased it to 3000 and everything is fine.