Things have been pretty broken for the last few Mono releases, it is always 2 steps forward and 1 step back with Mono, they don't dogfood it enough with real apps. When I saw you are using 2.6.3 I thought you were using a preview build as I did not know that the final 2.6.3 had been released. I've been waiting for it because things were broken under 2.6.1. I will report my findings after I have a chance to try it.
While I love Mono, I have never recommended anyone use it for important production sites and still don't because there are always some new issues or regressions. I don't have confidence in it base don my experience with it over the past 5 years. Occasionally a release works decently but it is always a crap shoot.