I did I search and couldn't find any other report of this issue which makes me wonder if this is actualy emulating a bug in dos?

Anyway, the bug is that interrupt 0x19 when executed from a .com file (I havn't tested any other file types) causes erratic behaviour (e.g. random characters being printed to the screen). This makes certain programs containing this interrupt to become unusable (though they will outside of dosbox, both in the windowsxp command prompt, and when booted off of a floppy at computer power-on).

I wasn't sure where to report bugs so this seemed like as good a place as any, seeing as I don't have any developers e-mail. Anyway, if any developer od dosbox reads this and would like example code to demonstrate this error just ask.