Everyone should note that this question has previously been asked, and answered ... in a slightly different form ... here.

Can we assume that there is no possibility whatsoever that the proc will be called twice (or more) at the same time?
If not, you need to add some code...

Try this & see whether it helps:

SELECT
  ObjName = OBJECT_NAME(referencing_id)
,  referenced_database_name
FROM sys.sql_expression_dependencies
WHERE referenced_database_name IS NOT NULL;

If you are happy to post the plan here as a .sqlplan attachment, someone here may be able to help you (but bear in mind the date ... not many...