Why did Humza Yousaf miss the vote on gay marriage?

With all the focus on Kate Forbes’ social views, it’s perhaps worth another look at Humza Yousaf’s own record on gay marriage. Back in November 2013, the now-favourite to succeed Nicola Sturgeon was a junior minister for External Affairs. He voted that month in favour of the general principles of the Marriage and Civil Partnerships (Scotland) Bill; however he subsequently missed the key final vote on 4 February 2014.