This is NOT a legal practice. If you work more than 40 hours in a workweek and/or more than 8 hours in a workday, you must be paid overtime for those hours. Your employer may not carry over hours from one week to another week to avoid paying overtime.
This is not legal. You get overtime for any hours worked over 8 hours in a day or 40 hours in a week. It's not an average of the two weeks.
Best of luck.