I want to export for example this:

but qgis crashes. Sometimes with an error message std::bad_alloc. But: My Mac has 8 GByte RAM and "just" 5,... something (of 8) GByte are used, moreover there is > 11 GByte free space on the disc.
Sometimes it crashes and you can have a look on an error report, like this one:

Now I noticed that everything works fine if I disclaim labels like "Unserer Lieben Frau". Is this a bug? It seems to be independent on the font used. Or... what can I do to export the results to PDF? Thanks a lot!!
Harald