What I assume happened is this:
You made enough entries in the Medical Expenses section to be able to show a medical deduction on Schedule A. What you didn't know is that the HSA distributions are automatically subtracted from your Medical Expenses on Schedule A.
This is because TurboTax assumes that you are entering all your medical bills (even the reimbursed ones), and then TurboTax subtracts the insurance reimbursement and the HSA reimbursement (distributions).
Note that the Colorado return starts (line 1 of form 104) with federal taxable income, not federal AGI, so it is perfectly possible to change the taxable income in the Itemized Deductions without changing the AGI.
To fix this, please go into the Medical Expenses interview, and towards the end where you are being asked for other or miscellaneous medical expenses, enter "Medical expenses paid by HSA" and the amount of the HSA distribution. This will balance out the expenses and the reimbursements, and your Colorado income will go back to where it was.
