On rare occasion, we have seen the SalesMail video link get pasted into the To box instead of the text message body when a SalesMailer hit 'Send Message' to share via text on an iPhone (like below). 

This seems to be a phone glitch on older iPhones and rebooting the phone usually fixes the issue.  Another workaround is to use the 'Copy Link' button on the share page instead of the 'Send Message' button.  Then you simply start a text message and then paste the SalesMail link into the body of the text message and send.