If a rich text contains a link to a mail, there is an AmetysRepositoryException thrown with the folowing message :
org.ametys.plugins.repository.AmetysRepositoryException: An object id must conform to the <protocol>://<protocol-specific-part> syntax: [mymail@example.com|mailto:mymail@example.com]
This happens in org.ametys.cms.content.CopyContentMetadataComponent.CopyAttachmentsHandler._copyIfAttachment(String)