The standout frame option affects nested note blocks, breaking their layout: the date and all the content is centered whereas it shouldn't.
While it is possible to circumvent this issue by putting the \note block outside of the frame block, the Beamer User Guide states that nesting it inside is recommended. It is also not possible to put it outside when using Pandoc.
Example
\documentclass{beamer}
\usetheme{metropolis}
\usepackage{pgfpages}
\setbeameroption{show notes on second screen=right}
\begin{document}
\begin{frame}[standout]
Standout frame
\note{Some notes}
\end{frame}
\end{document}
The
standout
frame option affects nested note blocks, breaking their layout: the date and all the content is centered whereas it shouldn't.While it is possible to circumvent this issue by putting the
\note
block outside of the frame block, the Beamer User Guide states that nesting it inside is recommended. It is also not possible to put it outside when using Pandoc.Example