Wrong macro expansion in pgfplots foreach and pgfplotsinvokeforeach - foreach

Question

What I am trying to do is to place a node on a path drawn with \addplot inside the body of \pgfplotsinvokeforeach, at a different pos and label at each iteration. However, the macros for the position and label only expand with their value at last iteration.
This is similar to what happens when one users addlegendentry instead of addlegendentryexpanded. If I use \expandafter then I get nonsense numbers.
Here is my minimal example:
\documentclass{standalone}
\usepackage{tikz,pgfplots,pgfplotstable}
\pgfplotsset{compat=1.18}
\begin{document}
\begin{tikzpicture}
\pgfplotstableread{
t 1.0 2.0 3.0
1 2 2 2
2 3 4 6
3 4 6 9
4 5 8 12
5 6 10 15
}{\loadedtable}
\begin{axis}[legend style={at={(-0.1, 1)}, anchor=north east},]
\pgfplotstablegetcolsof{\loadedtable}
\pgfmathsetmacro{\N}{int(\pgfplotsretval -1)}
\pgfplotsinvokeforeach{1,2,...,\N}{
\pgfmathsetmacro{\Dist}{#1/\N}
\pgfplotstablegetcolumnnamebyindex{#1}\of{\loadedtable}\to\Slope
\addplot+[] table[x=t, y index=#1]{\loadedtable}%
node[sloped, above,pos=\Dist]%
{\pgfmathprintnumber{\Slope}};%
\addlegendentryexpanded{%
Slope = \pgfmathprintnumber{\Slope}
and Dist = \pgfmathprintnumber{\Dist}}
}
\end{axis}
\end{tikzpicture}
\end{document}