The interval is used in RKF while this RKF is used in selection. Thing is as report is working fine with other weeks, it is definitely not an issue with RKF.
RKF (Receipt Value In Week 36-37) on LHS of designer:
Selection (Receipt Value In Week 36-37) on RHS of designer (under local structure): this selection is used in structure formula for actual bucket calculation.
Another thing In RKF we are not using interval 'ZZ_WK_SINGLE - ZZ_WK_SINGLE+1', we always used with some value example- ZZ_WK_SINGLE - 37 to ZZ_WK_SINGLE -36 etc. So, there is no chance that logic will get to week 47/2015. I validated that too.
One more thing - last week we also applied the next support pack, we moved from support pack 8 to support pack 16 (Netweaver 7.31 ). Not sure if this can have any impact.
Regards,
Pat.