How to reproduce:
In .vimrc, put set completeopt-=preview and set completeopt+=popup.
Then open a Python file and type something, for example prin. Press Ctrl-Space to show the completion menu. Press Ctrl-N to select print. A popup will appear.
The bug:
As opposed to what would have happened in a preview scratch buffer, the popup will display the function signature twice (see screenshot).

How to reproduce:
In .vimrc, put
set completeopt-=previewandset completeopt+=popup.Then open a Python file and type something, for example
prin. Press Ctrl-Space to show the completion menu. Press Ctrl-N to selectprint. A popup will appear.The bug:
As opposed to what would have happened in a preview scratch buffer, the popup will display the function signature twice (see screenshot).