I did the same research as @kansas3d – multiselect only saves the last of multiple fields on the xprofile edit screen. I am running BP 2.0.1 (WP 2.9.1), and have confirmed that rolling back to BP 1.9 (not BP 2.0) fixes the issue. I disabled all plugins and experienced the same problem in my custom theme (built on Bones, not TwentyFourteen-derived).
Converting multiselect to checkboxes allows for multiple value saving, but is not optimal. I have tracked down some similar tickets (#2176 from BP 1.2 and there’s another somewhere…)
