SSIS 2012: The environment reference n is not associated with the project

I have a package that I am updating. The package is executed by a Job Agent job. After deleting the package and then deploying the new version, I run a script that executes any necessary [create_environment], [create_environment_reference], [create_environment_variable], and [set_object_parameter_value] statements. However, when I start the job, it fails with the following error message (where "n" is a number which doesn't appear in any of the relevant SSISDB tables or views as an id of any kind): > The environment reference n is not associated with the project