Period Mapping for DEC month

*** Happy New Year ***

Hi Team,

Need some help understanding a behavior we are seeing with date-based period key to parameter conversion in ERP reports.
We are using report parameters like:
$StartPeriodKey[MMM-YY] / $EndPeriodKey[MMM-YY] which are derived from a date value.
What we are seeing:
• For Dec-24, using 28/12/2024 generates DEC-24
• Using 29/12/2024 / 30/12/2024 / 31/12/2024 generates DEC-25
• In 2025:
28/12/2025 generates DEC-26
27/12/2025 correctly generates DEC-25
Observation:
It appears the system is following a week-based year / ISO week logic, where the last few days of December fall into Week 1 of the next year, causing the period year to roll forward. (However, it is a PERIOD based application)