I've noticed that LuaTeX seems to incorrectly render continuing characters (like a circumflex, U+0302) when they follow Greek letters. I'm particularly interested in getting this to work with a monospaced font (because it comes up in code blocks):
\documentclass{article}
\usepackage{fontspec}
\setmonofont{DejaVu Sans Mono}
\begin{document}
\texttt{â \quad b̂ \quad ĉ \quad α̂ \quad β̂ \quad γ̂ \quad α̇ \quad β̇ \quad γ̇}
\end{document}
I've tried several fonts and haven't been able to find one that works, and I'm wondering whether it's a general font issue or more TeX-specific.