Following example shows only the square and lozenge (XeTeX, Version 3.14159265-2.6-0.99998) the other three symbols being shown as spaces whereas if unicode-math is removed, the symbols are shown correctly. Is there a way to show the symbols correctly whilst using unicode-math?

```
\documentclass{article}

\usepackage{amssymb}
\usepackage{unicode-math}

\begin{document}
$$a\blacksquare \blacklozenge \blacktriangle \blacktriangledown \bigstar b$$
\end{document}

```