task.transitionToTarget() does not change the target of a task immediately

transitionToStatus and transitionToImportance have instantaneous effect on the attribute of the task, but as you can see in the attached example transitionToTarget does not, it needs the bug to reload:

In [1]: b = launchpad.bugs[123456]

In [2]: t = b.bug_tasks[0]

In [3]: t.status
Out[3]: u'New'

In [4]: t.transitionToStatus(status="Invalid")

In [5]: t.status
Out[5]: u'Invalid'

In [6]: t.target
Out[6]: <project at https://api.staging.launchpad.net/beta/bughelper>

In [7]: a = launchpad.projects["amarok"]

In [8]: t.transitionToTarget(target=a)

In [9]: t.target
Out[9]: <project at https://api.staging.launchpad.net/beta/bughelper>

In [10]: b.lp_refresh()

In [11]: t.target
Out[11]: <project at https://api.staging.launchpad.net/beta/bughelper>

In [12]: b = launchpad.bugs[123456]

In [13]: t = b.bug_tasks[0]

In [14]: t.target
Out[14]: <project at https://api.staging.launchpad.net/beta/amarok>