Strange rendering bug when using LuaLaTeX, Polyglossia, Cambria/Consolas font and/or texttt

Question

I’ve found a rather strange bug, where the letter ‘å’ is sometimes (though very rarely) incorrectly rendered when using LuaLaTex. I’ve managed to reduce it to the following minimal document exhibiting the problem:

\documentclass{article}

\RequirePackage{polyglossia}
\setdefaultlanguage{nynorsk}

\RequirePackage{fontspec}
\setmainfont{Cambria}
\setmonofont{Consolas}

\begin{document}

Here the word språket is rendered incorrectly. \texttt{Monospace.}

\end{document}

The output (using LuaLaTeX from TeX Live 2015 on a Windows system) is:

The strange thing is that I can make the problem go away by removing either one of the \setdefaultlanguage, \setmainfont, \setmonofont lines or the \texttt command, or by changing the ‘å’ to an ‘ø’ or an ‘æ’, or by changing LuaLaTeX to XeLaTeX:

So I don’t know if the problem is with Polyglossia, the Cambria font, the Consolas font, the fontspec package or LuaLaTeX. This makes it difficult to report as a bug. Any idea where the bug is and what causes it (and perhaps a workaround)?

Answer 1

Using test releases of luatex 0.85 and the luatotfload from github sources, I get

So this should work in texlive 2016.