Database mail error Msg 14607 in SQL Server 2012

I have set up 3 database mail profiles in a SQL Server 2012 STD edition instance.  One profile is for the DBA admin group and is the default.  The other two are for an application. The app has a dev and a test database in the same instance.  So I tried setting up logic in a proc to check the name of the database, and if it ends with DEV, then use the DEV profile, otherwise it uses the TEST profile.

I wanted to use a variable to send to sp_send_dbmail for the @profle_name.  The 2 profiles are 'APP_DEV' and 'APP_TEST'.  Each has an app group email assigned.  I also have added the logic for additonal recipients which works fine.

Basically it's like this:

DECLARE @mail_profile_name sysname
DECLARE @subj varchar(80) = 'Testing....'
DECLARE @recips varchar(100) = 'mail1@abc.com;mail2@abc.com'

if this is the dev database....
   set @mailProfileName = 'APP_DEV'
else
   set @mailProfileName = 'APP_TEST'

exec msdb.dbo.sp_send_dbmail
    @profile_name = @mailProfileName,
    @recipients = @recips,
    @body = @body,
    @subject = @subj

I get this error: 
Msg 14607, Level 16, State 1, Procedure sysmail_verify_profile_sp, Line 42 profile name is not valid

If I hardcode the profile name in the call to sp_send_dbmail, it works fine. 

exec msdb.dbo.sp_send_dbmail
    @profile_name = 'APP_DEV',
    @recipients = @recips,
    @body = @body,
    @subject = @subj

I don't understand why the call to sysmail_verify_profile_sp from sp_send_dbmail is failing.  Anyone have any ideas?