Thanks for your reply, I can see what you mean now.
Unfortunately, the default_schema setting is a user property that is automatically ignored by SQL Source Control. SQL Source control uses our SQL Compare
engine to compare the differences between the live database and what's stored in Source Control. It's a default option in SQL Compare to ignore the 'user properties' and SQL source control uses the default SQL Compare options. We have an open feature request to allow the user to configure the SQL Compare engine options, which you might like to vote for here
Currently the only workarounds I can think of are:
1) Delete user1 from DB2 and then 'get' the complete user from source control.
2) Use SQL Compare to deploy the user from Source Control to the database, and turn off the option: 'ignore' > 'user properties'
I hope this helps explain.
Let me know if you need any more information.