You need to have the bow equiped when the attack registers.
Similarly it used to be possible to HA on bow > swap to 2H and proc the forcefull passive, because 2h was the active weapon when the attack registered on the target.
Answer is that game has huge problems with responsiveness. For example, you have pretty standard lame 2H/Bow PVP setup. You roll-dodge with 2H and send bar swap command in process. On roll-dodge end you will take bow and receive major expedition. Looks ok. But if you do it vice versa - i.e. roll-ddoge with bow and bar swap to 2H immediately after that you will receive nothing.