Another weird observation: Kurier is not working at all.

Plus, Asana-Math and Xits are not installed as part of ConTeXt scheme.
Should I add them? (It's size is 0.5 + 1.5 MB while in tar.xz.)

Hans, maybe you could add Tim's example into your testsuite (but each
math font should be surrounded with \bgroup...\egroup or start/stop).

Mojca