Why doesn’t turbo tax take into account the 15 day rule for non residents working for ct company. If working less than 15 days in ct, no ct tax income tax is owed

I’m a remote worker working from home in NJ for an ct company,. I do go onsite for a few days a year. According to the below link, non residents don’t owe tax if they’re not working in ct for more than 15 days, but when I do my ct non residents return it always has me owing a little for the few days I work onsite. https://portal.ct.gov/-/media/drs/publications/pubsps/2015/ps2015-6pdf.pdf?rev=4cb2fe9156ab4de9a3c8349c146ad8fb&hash=FA57C797B94B251DE884475B6D606200#:~:text=If%20an%20employer%20expects%20that,compensation%20paid%20to%20the%20employee.