cloner.js selects create buttons by class and passes them all to OO.ui.infuse: https://gerrit.wikimedia.org/r/plugins/gitiles/mediawiki/core/+/e9e784a09e9dce43b832225945b2d57f7a2bde01/resources/src/mediawiki.htmlform/cloner.js#32
This causes problems when there are multiple cloner fields on the page: the data for the first create button overwrites the subsequent create buttons (see T270960 for details).
This caused problems while working on T208687: Convert SecurePoll to use OOUI, since there are multiple create buttons on the CreatePage form.