Part of where condition ignored after upgrading to 72

Hi folks,

We have recently upgraded to 72 and in testing we have discovered that part of our SQL where condition is now ignored when using IS NULL in conjunction with OR operator.

For example;

If I have 10 records where ABC indicator = 'A' and 5 records where ABC indicator is null for a total of 15 records;

in 68 environment this below statement would return all 15 records:

select * from MSEG where BLDAT = '20140320' and (MAABC = 'A' or MAABC IS NULL)

in 72 this above statement is only returning the 5 null records.  Any other criteria within the parenthesis is completely ignored.

-Patrick