Who Has An Explanation For This

My fiance was checking her email on her phone when she came across this. First of all, 'no sender' and 'no subject', no 'content'. Then, look at the date in the upper right hand corner. This predates the internet itself and goes back to the time of something called the ARPANET, long before email really existed. She grabbed a screenshot of it and sent it to my phone. Then by the time she went back to her email later, it was mysteriously gone and she hadn't deleted anything. So what's up? I need all computer nerds and cyber sleuths to give me their thoughts. If anyone has any ideas you can use the comment section below. Is this a hacking? Is this just some weird glitch? Has anyone ever had something similar? Let me know.