On rare occasions keyboard shortcuts for copy/paste won't work in Station.
We are currently investigating the case and we'll soon find a permanent solution.
In the meantime, use your mouse to copy/paste instead of keyboard shortcuts to correct the issue:
Select and right click on what you want to copy
Click "copy" in the contextual menu
Paste with your regular keyboard shortcuts (CMD+V or CTRL+V)
You will only have to do it once and it will work again after that.