Edit soldier from pre-combat deploy screen and try to dual class soldier; press the dual-class skill and nothing happens.
Tried a few other soldiers, same thing. Then esc/back to main geoscape and I see the dual class window (several overlapping).
Esc/back to close all of them.
Dual classing works fine when edit soldier from the personnel screen.
Surely not intended behaviour ? Using latest behemoth update (don't have the dlc).