Multipage Webforms w/Ajax Breaks Proceeding to Second Page

Issue Summary

I've created a simple two-page form using the Webform module (version 6.x-2.6) using a pagebreak form component to separate the two user-input sections. This runs fine by itself, but when I enable Ajax for that webform and try to proceed to the second page, I get this instead of the second page:

{ "status": true, "updaters": [  ], "debug": [  ], "messages_error": [  ], "messages_status": [  ], "messages_warning": [  ], "redirect": null, "preview": null, "form_id": "webform_client_form_37", "options": { "enabled": true } }

Any ideas?