KB39382: "Invalid Expression" error message appears when attempting to revalidate an expression with both IF and IN functions in MicroStrategy Developer 9.x - 10.x

SYMPTOM:
In Strategy Developer 9.x - 10.x, the following error message appears when attempting to revalidate an expression with both IF and IN functions:

Error verifying form expression
Invalid Expression.

• In Strategy Developer, create an attribute using the following expression:    
  
  Sample Code/Error
  IF((BRAND_DESC In ( "A", "B")),  "C",  "D") 
  
   
  
• Validate the expression and save it, as the image shown below:
  

• Edit the form again. The expression is changed to:  
  
  Sample Code/Error
  IF(( In "A" In "B"), "C", "D")
  
   
  
• Validate the expression again, The validation fails and the following error occurs:
   

CAUSE:
This is a known issue with Strategy Developer 9.x - 10.x.
 
 
ACTION:
Strategy is investigating the issue and will continue posting updates as soon as they become available.