Same thing happened to me. My tax liability went up when I entered in the long-term capital gains. When I investigated (Federal Review tab/ 2024 tax breakdown) I discovered that the increased tax liability was for my Affortable Care Act premium increase. Affortable Care Act premiums are based on MAGI which includes capital gains income. In other words, the capital gains income lowered my health insurance premium tax credit...hence more tax liability. Hope this helps.
