Did you install TurboTax in a location other than your main system drive?
Are you plugging USB devices in and out by any chance? TurboTax can sometimes see a change in USB devices as a different system and ask for a license activation. I once forgot I left a thumb drive in place, and when I started TurboTax, it asked me for re-activation. Once I removed the thumb drive, then TurboTax started normally without asking for the license code again. Another user says it can happen with an SD card as well.
Here's how to speak to TurboTax Customer Support:
Hours are 5AM-9PM Pacific (8AM-12 Midnight Eastern) 7 days/week.
Or you can use this contact form to get a phone number, or it may schedule a callback.
https://support.turbotax.intuit.com/contact