+ overlay specification broken?

Question

Since a recent update, the +- overlay specification doesn't seem to work anymore, for environments at least. I'm up to date with TexLive 2015 (beamer 36461 (3.36)). Consider the following MWE:

\documentclass{beamer}

\begin{document}
\begin{frame}
  \begin{block}{On the first slide}
  Hello
  \end{block}
  \begin{block}<only@+>{On the second slide}
  Goodbye
  \end{block}
\end{frame}

\end{document}

I expect the second block to appear on the second slide (that's what it used to do until recently) but the two blocks are on the same slide.

Answer 1

The behaviour is the intended behaviour as documented in the manual (90):

\begin{itemize}
\item<+-> Apple
\item<+-> Peach
\item<+-> Plum
\item<+-> Orange
\end{itemize}

The effect of the +-sign is the following: You can use it in any overlay specification at any point where you would usually use a number. If a +-sign is encountered, it is replaced by the current value of the LaTeX counter beamerpauses, which is 1 at the beginning of the frame. Then the counter is increased by 1, though it is only increased once for every overlay specification, even if the specification contains multiple +-signs (they are replaced by the same number). In the above example, the first specification is replaced by <1->. Then the second is replaced by <2-> and so forth.