I'm currently using a latest CC version Ai and i encounter a problem/bug. When i create a clipping mask on a multiple objects for a final file. For example: An A4 artboard, i just did a last step clipping mask into A4 size and save it. Then i close the file. when i reopen the same file, my multiple objects all becoming a flatten object?? (Can't be select separately). This issue really give me a heart attack.

It happened on my vector artwork and image combined vector file twice so far. Which i not dare to use clipping mask recently. PLEASE help to look into this bug issue, Thanks!

Regards,
Edwin Yuen
(Adobe user)