Using PRIOR/XRANGE with cross-dim (fails when crossing years)

@PRIOR("AAFPU_EOP"-&gt

I have a dynamic calc member called AAFPU_BOP with the following member formula:

@PRIOR("AAFPU_EOP"->"SalesChannel_Total",,@REMOVE(@XRANGE(&PrevYear->"Jan",&Y2->"Dec"), &PrevYear:&Y2->"BegBalance"));

I want the member to be populated with the previous month AAFPU_EOP->SalesChannel_Total. This works for all months except January where it ignores the cross-dim SalesChannel_Total. Why is this and how can I fix it?