Variable watch within state machines is broken

Watching variables within states seems to be broken. See repro steps for details.

1. Create an anim bp
2. Add a state machine and create a state within it
3. Setup some logic within the state and drive it via a float bp variable
4. R-click on the variable node and watch the value
5. Set the value of the variable via the Anim Preview Editor window
   1. Note that the value of the watch in the graph will remain zero
   2. Expected behaviour: the value should match what is set in the Anim Preview Editor window
   3. This only occurs within states. If the logic is replicated in the top level of the graph then the watch behaves as expected.