This is working as designed. The changes made to the time scale under Options: Time- scaled Value are intended to be temporary for that user session. To retain the changes even after a user logs out and back in, make the change from the Options: Configure - Fields page instead.
From the above example, navigate to Project Team Details --> Configure
Then click on the List Column Section tab and select Fields. Click on the Properties Icon for the Time Scaled Value field, and make the changes to the time scale here:
Then even after logging out and logging in back, the start date of the time scale will retain the changes. In this example, the change was that the Start Date was set to start in January 2017.