Master Enslave MR roll

[Ygorl]

3% isn't that unusual to see once in a while. Was your vampire the only leader there, or were there lots of other leaders that weren't enslaved? If you've got ten leaders with MR 23, the chance of one of them getting enslaved is close to 30%. Even if you've seen lots of truly unlikely things, well, there are a lot of people playing Dominions, and chances are some of them will see several very unlikely things.
It may well work other than how it is advertised, of course.