Just to be clear, you switched from Self-only HDHP coverage in June to Family for the rest of the year? It appears that TurboTax thinks that you had Self-only coverage for Jan-May and no HDHP coverage for the rest of the year.
Note that the HSA contribution limit is pro-rated based on the number of months you had HDHP coverage.
Because of the last-month rule, since you had Family coverage HDHP on December 1, 2024, you are entitled to use the Family HDHP contribution limit for all year ($8,300).
Please go back into the HSA interview and make sure that
1. you entered HDHP coverage for all year, Self in the first half and Family for the rest.
2. that the code W amount on your W-2 in box 12 is indeed 3,660.
3. Conversely that the amount you contributed directly as a personal contribution is 3,660 - or some combination of #2 and #3.
4. Check that you told TurboTax that you had HDHP coverage for at least each month, if you did.
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