Contained Databases use TempDB Collation for Temporary Stored Procedure names instead of CATALOG_DEFAULT
Meta-data (mainly name resolution) for temporary objects created within a Contained Database is supposed to follow the Collation rules of CATALOGDEFAULT (i.e. Latin1General100CIASKSWSSC ). And this is the case for Temporary Tables, Table Variables, and even Indexes on Temporary Tables.
But, meta-data for Temporary Stored Procedures (i.e. their names) is not using the CATALOG_DEFAULT Collation, but instead is using the Instance / Server / tempdb Collation, which is expected behavior for Non-Contained Databases.
I have tested this on SQL Server 2012 SP4, and SQL Server 2016 SP1.
Solomon Rutzky commented