Please, consider the following simple example:
\documentclass[tikz, border=3mm, preview]{standalone}
\begin{document}
\begin{tikzpicture}[
every node/.append style = {text=blue}
]
\node {root}
child {node {left}}
child {node {right}
child {node {\textcolor{red}{L} child}}
child {node {R child}}
};
\end{tikzpicture}
\end{document}
which gives:
Why text in L child node hasn't red L and blue child? Interestingly, if I change color orders:
child {node {L \textcolor{red}{child}}
then result is as expected: blue L and redchild:


forest, maybe it is worth that you make an answer to it? – Zarko Nov 08 '16 at 01:05\tikz\node[text=blue]{{\color{red}L} root};will show the problem. Even more irony:\tikz\node[text=blue]{{\color{.}L} root};– Symbol 1 Nov 08 '16 at 03:24