From what you're describing, it sounds like the system is working correctly.
However, you're focusing on Form 104 line 10, Colorado Taxable Income, rather than line 11, Colorado Tax. (Colorado forms available at 2023 Income Tax Forms | Individuals & Families.)
Although line 10 can include more than just your Colorado income, line 11 makes a tax computation based on the Colorado portion of your income.
Since you're a Part-Year Resident or Nonresident of Colorado, TurboTax will generate Form 104PN, Part-Year Resident/Nonresident Tax Calculation Schedule 2023. Form 104PN takes into account your Colorado income (as opposed to your total income), and computes your apportioned Colorado tax on line 36.
This tax is then transferred over to line 11 of your Colorado Form 104.
