Since Bug 4868 implementation, subfields subfield cloning and uncloning is broken : uncloning generates a javascript error and cloning always clones the first subfield. Also, there are more errors with a cloned field. I think it comes from 2 points : - <a> replaced <span> - class="buttonPlus" and class="buttonMinus" disappeared One must check the javascript of addbiblio.tmpl and authorities.tmpl.
This works for me in current master. Please re-open if you find otherwise.