Hi and thanks for reaching out. My name is William. I'm a Microsoft Windows Certified Professional and Systems Administrator. I'll be happy to help you out today.
Despite the chatter on the Internet that this is a bug, this is by design. Script extensions like batch, vbs, powershell, executables, reg files are considered a security hazard as they could execute nefarious commands without the recipient knowing what they are. To work around the issue, rename the file to modify the extension before sending it, e.g. RunMe.bat_