Symptom:
In Unified Call Studio applications, the element data and session variables substitution result incorrect substitutions.

Conditions:
Using data variables in Call Studio application.
The problem occurs in the below scenarios. 
1. Define a data variable with name - Variable1.
2. Define another variable with name VARIABLE1. 
3. Substitute both elements variables in the substitution. E.g. TTS audio text construction. 
The Unified Call Studio allow this configuration. But in the actual substitution evaluation only one of two variables value is used. Which variable will be used will be predictable.