Exiting a stacked BT may cause premature completion

In a typical case you create a BT (say 'A') with its agent set to loop = false.
Then you stack another BT (say 'B')
When B returns `done`, the agent will disable. However continuation is expected until the root BT has returned `done`.

Tried patching this in `UGigAdapter`. Works, mostly; however this is hackish and does not resolve the actual issue.