Birthdate is one day less when viewing user attributes in Studio.
Studio | People | Users
Birthdate is stored as a datetime in UTC (Coordinated Universal Time) standard time. When displayed in different timezones, this can cause the date to change.
For example EST (Eastern Standard Time) is 5 hours earlier than UTC. A birthdate of Jan 2 1990 is stored as 1990-01-02 00:00 UTC, and becomes 1990-01-01 19:00 EST, displaying as Mon Jan 1 1990.
There is currently no workaround for this issue. Please check the current status of this issue on the Known Issues Tracker. (Issue ID: MAGIC-7697)