I was customising a people search result web part this week and couldn't figure out why the mobile phone field was not rendering in the results. I could see it was in the AD properties, was making it through user profile import and then helped it through to managed metadata in the search results, I even checked the raw XML for the search results which showed it there as well. So I was down to checking my XSLT, I had camel cased the name of the field in my select code, as is my habit with coding to make it easily readable, but the XSLT was looking to match the case returned by the search results which was all in lower case.
A quick crrection and refresh and they all appeared as they should. Another little puzzle solved...