I was using this plugin on a Genesis child theme site.
I then added the WPML plugin and created a translation for an AgentPress listing CPT.
The original listing has images attached. The translation doesn't show attached images at forsit which should be the normal behaviour I suppose. But then if I opn the Media uploader, images appear in the Gallery Images metabox. Then when I close the media uploader, a popup appears and says "this page has caused an error".
This is happening on a local dev installation.
I don't know if the issue is caused by WPML or this plugin though.