Existing code(in operator) of corticon 5.5 version not worki

Hi Team,

I have an already existing code related to in operator working correctly in version 5.5.When I migrated to
5.7 same code is giving an error.

Here is the example of code written in rulesheet.

myObj.effectiveStartDate in [myOtherObj.effectiveStartDate..myOtherObj.effectiveStartDate.addMonths(2))

The above code gives me error of unbalanced parenthesis error in 5.7.As per corticon documentation this
should not give an error as I need to include the date near to '[' bracket and I do not need to include
date near to ')' bracket.This piece of code is working in version 5.5 but not in 5.7

Thanks
Kapil Mehta