AutoCAD 2019 User Data Hotfix can be downloaded here.
“To improve user data privacy in compliance with GDPR requirements, we’re providing this hotfix to eliminate the transmission of user serial numbers when using an Autodesk program to access an Autodesk download site.”
Similar GDPR hotfixes are available for other products and versions. Currently I found these:
AutoCAD Architecture and AutoCAD Mechanical 2017 User ID Hotfix
AutoCAD Architecture 2016 User ID Hotfix