StateTree no longer binds to the properties of an output variable from a task or an evaluator. Selecting one of the child properties of the output variable results in an error string being displayed in the StateTree editor saying "Property is bound to Evaluator GetCharacter property Character.BaseEyeHeight, but binding source type '' does not match property type 'Float'."
While this does not work for outputs of a task or an evaluator, you can successfully bind to sub-properties of the schema's Context variables.
Expected Result: The Duration is bound to the float property of the Character.
Actual Result: The binding fails with an error message that the source and target property type is not the same.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-197989 in the post.