I think that is probably a true assumption. There are some risks in using the bleeding edge of Mono from svn. You probably should file a bug report with Mono. The one good thing with running Mono from svn is when they fix it you can get the fix right away but the downside is you also see the regressions and new bugs as they introduce new features. As I understand it the CSS Adapter support won't be in an official release until version 2.0 which is targeted for the June time frame.
Best,
Joe