Beamer uncovering items which should be invisible

Question

invisible shows items that are hidden with transparent

After trying to adapt this answer to "Beamer: Uncover underbrace", I find that when I change transparent to invisible in \setbeamercovered I am not getting the result I would have expected. When transparent, I get the desired uncovering order, but this seems not to be preserved as I move to invisible.

MWE

\documentclass{beamer}
\setbeamercovered{transparent} % Change to invisible. 
\begin{document}
\begin{frame}
\begin{align}
\onslide<1->{\text{Something} & = \text{Slide 1 onwards} \\[1em]}
& \qquad \onslide<2->{+} \onslide<3-> \underbrace{ \onslide<2->
\text{Slide 2 onwards}
\onslide<3-> }_{\text{Slide 3 onwards}} \onslide<2->
\end{align}
\end{frame}
\end{document}

Answer 1

I added a missing set of {} as well as the \notag command to stop (2) from showing up on the first slide.

\documentclass{beamer}
\setbeamercovered{invisible} % Change to invisible. 
\begin{document}
\begin{frame}
\begin{align}
\onslide<1->{\text{Something} & = \text{Slide 1 onwards} \\[1em]}
& \qquad \onslide<2->{+} \onslide<3->{\underbrace{ \onslide<2->  % <----- Added {
\text{Slide 2 onwards}
\onslide<3-> }_{\text{Slide 3 onwards}}\\} \notag % <----- Added }, \\ and \notag
\end{align}
\end{frame}
\end{document}