There are two copies of the content of your clipboard
There should be only one paste.

_Please provide as much info as you readily know_
No output available.
Microsoft Data Science for VS Code Engineering Team: @rchiodo, @IanMatthewHuff, @DavidKutu, @DonJayamanne, @greazer, @joyceerhl
Repro-ed. In particular, this issue only appears to show up when the paste destination is an ipynb that has been saved to disk. I.e. copy from untitled -> paste to titled / copy from titled -> paste to titled trigger the error; copy from titled -> paste to untitled / copy from untitled -> paste to untitled do not. Thanks for the bug report!
This seems to happen only on mac, I can't repro it on windows or ubuntu.
@DavidKutu just noticed while going through open issues that this is likely a dupe of microsoft/vscode-python#11796, and in that issue multiple users reported the bug with Darwin as the OS.
@joyceerhl yeah, it seems to be the same issue...
@Saafo I've tagged you in the other issue, please follow that one.