Hi ​@Cuộc Sống Thật Đẹp! First, I redacted the file link you posted in order to protect your file. It looks like it may have possibly be a demo, but I did this just in case..

I just took a look at the file, but I wasn’t able to replicate the issue. It seemed like I was able to duplicate the frame as expected.

Can you post a screen recording of what happens to you when you try to duplicate yourself?

Also - can you try the following? If you’re on the desktop app: in the top toolbar, go to help > troubleshooting > reset Figma and restart

 

Can you see if that helps fix this for you? Let me know.