Calendar attachments getting corrupt by opening it in airplane mode - 0 Byte

When I am trying to open a PDF or JPG file inside my calendar while the airplane mode is enabled the attachment is getting corrupt. As well when I am connected to a weak network and cancel the download process.

 I have faced the problem with Outlook.com and Exchange mail accounts.

After opening the attachment I am getting the below screen:

When I return back to the calendar item, the size of the PDF or JPG file is now just 0 bytes and the file is corrupt. Even when I am trying to re download it with a proper connection.

Is this a known bug of iOS? I have tried this with several iPhones and different iOS versions.