How to claim the 'Spousal or Common-Law Amount' for a spouse who immigrated during 2020 (December 13, 2020)

[William b-squared]

My client's spouse immigrated to Canada in mid-December 2020.  I prepared his return showing his world income for the period he resided in Canada.  I provided details regarding his Canadian source income (Zero -0 ) while he was non resident as well as his World Income during the period of Canadian Residency ($675 CDN).  His return is fine, there is no tax payable and his personal amount (etc.) was properly pro-rated based upon the Date of Entry.  The problem arises when my client claims the 'Married Amount' non-refundable tax credit.  The software is calculating the claim based upon the minimal income reported during the period of Canadian residency, rather than basing it upon his World Income for the year.  I have confirmed with the CRA that the claim should be calculated based upon his World Income for the entire year ($8100 CDN).

Has anybody else encountered this issue and is there a solution and/or work around for it?  

I could prepare the returns as two individuals rather than a family and force the correct resolution, but I am hoping that will not be required.

Any assistance would be greatly appreciated.  Please advise if my understanding of the proper way to report this situation is in fact incorrect

Thanks!