Position of under accents

[eg9]

Description

Under accents are placed wrongly, taking into account the whole.depth of the resulting math atom instead of the base only. This happens both for wide under accents and fixed width one.

Add info or delete as appropriate:

• Relevant for XeTeX: yes
• Relevant for LuaTeX: yes
• Issue tracker has been searched for similar issues? Yes

Minimal example demonstrating the issue

\documentclass{article}
\usepackage{unicode-math}

\linespread{1.5}% just to get more space between lines

% possible fix?
\NewDocumentCommand{\fixmathunderbar}{m}{%
  \mathunderbar{\kern0pt#1}%
}
\NewDocumentCommand{\fixthreeunderdot}{m}{%
  \threeunderdot{\kern0pt#1}%
}
% end of fix

\begin{document}

$\mathunderbar{e}+\mathunderbar{e}_1$
$\mathunderbar{f}+\mathunderbar{f}_1$

$\fixmathunderbar{e}+\fixmathunderbar{e}_1$
$\fixmathunderbar{f}+\fixmathunderbar{f}_1$

$\threeunderdot{e}+\threeunderdot{e}_1$

$\fixthreeunderdot{e}+\fixthreeunderdot{e}_1$

$\hat{e}+\hat{e}^1$

\end{document}

Output with LuaLaTeX

Output with XeLaTeX