It's a very long time since any release of MS SQL Server has had that default. The default has been Latin1_General_CI_AS for at least 6 years, and I believe for quite a bit longer. Obvioulsy if you are working with MS SQL Server 2012 you must have set the instance default to SQL_Latin1_General_CP1_CI_AS on installation of one or more of your systems, and left it at the default on one or more.

The solution is first to find out what each instances default collation is. Then change the default collation of whatever instances can be changed with least trouble. You may also have to change column collations explicitly for any tables created with a column or columns using the instance default collation. If you are lucky the database schema designers will have explicitly declared collations for all character type columns so that that won't be necessary (you could still get errors with temp tables and maybe with sql local variables, so ).

Sometimes the easiest way to change the default collation for an instance is to uninstall it and reinstall with the correct default collation, but you need to be very careful that you don't lose any data if you do it that way. The alternative is the Rebuild Master utlity (if it still exists - I haven't used in recent versions of SQL Server) but some people find that harder than the other way even when they have lots of data to preserve.