I have a weird issue with this simple plot. I need to draw four couples of plots, each made by an approximate curve (continuous line) and the real curve (dashed line). For some reasons I can't understand the plot (t,y_p20a) is dashed, but it shouldn't be. Another weird thing is that if I rearrange the plot couples in a different order, such as 12 34 78 56, the issue is still on the seventh plot (which is, in this case, the number 5). Any idea?
\documentclass{standalone}
\usepackage{filecontents}
\begin{filecontents*}{data.csv}
t,y_m20r,y_m10r,y_p10r,y_p20r,y_m20a,y_m10a,y_p10a,y_p20a
0,0,0,0,0,0,0,0,0
1,0.022341,0.0099981,-0.0082633,-0.015207,0.018097,0.0090484,-0.0090484,-0.018097
2,0.03993,0.017993,-0.015022,-0.027751,0.032749,0.016375,-0.016375,-0.032749
3,0.053529,0.024287,-0.020482,-0.037983,0.044449,0.022225,-0.022225,-0.044449
4,0.063789,0.02914,-0.024824,-0.046211,0.053626,0.026813,-0.026813,-0.053626
5,0.071269,0.032777,-0.028206,-0.05271,0.060653,0.030327,-0.030327,-0.060653
\end{filecontents*}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotstableread[col sep=comma,header=true]{data.csv}\data
\begin{document}\begin{tikzpicture}\begin{axis}
\addplot table[x = t, y = y_m20a] from \data;
\addplot [dashed] table[x = t, y = y_m20r] from \data;
\addplot table[x = t, y = y_m10a] from \data;
\addplot [dashed] table[x = t, y = y_m10r] from \data;
\addplot table[x = t, y = y_p10a] from \data;
\addplot [dashed] table[x = t, y = y_p10r] from \data;
\addplot table[x = t, y = y_p20a] from \data; % THIS ONE SHOULD NOT BE DASHED
\addplot [dashed] table[x = t, y = y_p20r] from \data;
\end{axis}\end{tikzpicture}\end{document}