Sorry bro, but this was intentional omission on the part of the applicant. They knew that declaring an MBA can adversely affect their chances of getting a SP for a PG diploma hence the omission. They 100% knew why their lawyer suggested it and they went along with it. IRCC is not stupid (well they kinda are, but not in this regard
), they see this trick all the time, and if this degree is included in any application going forward, it would most likely be flagged as misrepresentation = ban.
Even if they do not claim points for it in their PR application, simply mentioning it in the Personal History will raise suspicion cos a degree is not something you randomly forget to mention, especially in a study permit application.
I agree with the advice to lawyer up.