Using Fieldname as EXTENT argument in a DB query terminates

Hi Guys:

A simple innocent looking query below.

Can anyone tell why this query wont work in Progress 11.7.2 ? But works perfectly in Progress 11.5 ?

Culprit is usage of customer.months as the extent argument in the Where clause. But any reason why progress would deem this as an illegal ? This query actually disconnects you from the database.

Such fatal consequences and yet could not find a mention of this in their release notes. Anybody here who knows about this issue/upgrade?

DEF VAR p AS INT EXTENT 2 INIT[10,20].

FOR EACH Customer

WHERE Customer.JoinDate + p[customer.Months] <= TODAY no-lock:

MESSAGE Customer.CustName.

END.

Note: Customer.months is an integer field with values either 1 or 2.