Ran into the same problem johnofwax did. There doesn't seem to be a way to drop divers off a boat with TRANSPORT UNLOAD without the boat taking them to shore.

Upon further testing I was able to get subsequent task destinations to show after the first. They need to be linked to the previous task's trigger as well as the new create task.

I am also unable to get the task destination to show up after the first.

I've experienced this as well, although not necessarily when using weapons or items. Sometimes it seems to have to do with stance - I've had a medic in a crouched position not follow an order to heal someone (or himself) but after I order him to stand up he is able to follow the orders.