Happend to me right now after yesterdays stable update.
Set master arm on, A/G mode on, selected JSOW/A, switched from WP1 to WP2 and hit WPDSG. Nothing happend, the TGT was flashing in the HUD for a sec but went instantly back to WP. Bug or lacking kowledge - the only topic I found was this...
EDIT: Ok it works now like a charm on all maps and configs...don't know why and sorry for bumping this up - must've been a Human Interface Bug...