When my wife went to reply to email it sent blank email in reply without pressing Send

Both my wife and I use Em Client and both like the program.  My wife went to reply to an email and it instantly sent a blank email in reply to the person she was responding to.  No signature or even there original email was in the email.  Not sure what happened or if anyone else has had this problem. She closed the program and went back in and it started working right again.