Something doesn't sound right.  There should be no adjustment against Fed AGI, not on IT-203 and not on CT-1040NR (or any of its schedules).

All of the telecommuting compensation (plus NY-source income received during CT residency - e.g. year-end bonus) should be reflected on CT-1040AW Column B.  Whether there's any CT-source income in Column D would depend on whether she had any CT workdays during the NR period.  The total of those two columns will flow through to CT-SI, which will be used to determine CT-tax on an as-if basis on CT-1040NR.

Unless your client had actual NY workday during her CT residency or received income accrued to NY, there should technically be no creditable NY tax.  And if she did have NY workdays or income accrued to NY, you will need to override the input for other state tax credit to limit the application.

This won't be good news to your client.