Usage of ApplicationIntent Parameter in SSIS connections
This is by design

Depending on the SNAC protocol you are using there is a slight variation in the application intent connection string property.

When using SQL Native Access Client SQL OLE DB, the application intent connection string should be specified with a space: 'Application Intent'
When connecting using SQLClient or ODBC specify 'ApplicationIntent' with no space

https://blogs.msdn.microsoft.com/alwaysonpro/2013/08/02/connect-to-sql-server-using-application-intent-read-only/