I have the following tree in which the left-most leave is out of sync:
\documentclass{minimal}
\usepackage{tikz-qtree}
\begin{document}
\begin{tikzpicture}
\tikzset{level 1+/.style={level distance=3\baselineskip}}
\tikzset{level 2+/.style={level distance=2\baselineskip}}
\tikzset{frontier/.style={distance from root=8\baselineskip}}
\tikzset{every tree node/.style={align=left, anchor=north}}
\tikzset{every leaf node/.append style={text depth=0pt}}
\Tree[.S
[.NP er\\he ]
[.NP
[.Det das\\the ]
[.N Buch\\book ] ]
[.NP
[.Det der\\the ]
[.N Frau\\woman ] ]
[.V gibt\\gives ] ]
\end{tikzpicture}
\end{document}
I followed
aligning several trees to the baseline
and added \tikzset{every leaf node/.append style={text depth=0pt}}
, but this does not have any effect.