Exactly what amount was lowered? Do you mean the refund on line 35a of your 2025 Form 1040? Or are you talking about the amount you actually received, which could be less than line 35a? An offset would not be reflected on your Form 1040. And what are you comparing it to? Line 35a on your 2024 Form 1040? If line 35a on your 2025 tax return is significantly lower than line 35a on your 2024 tax return, compare the two 1040 forms line by line to see where the significant differences are.