In Talend Jobs, it is possible to use the implicit context load feature that allows context variables to be dynamically loaded at run time, thus not providing any value for these variables in the Job itself. For more information, see Using the Implicit Context Load feature in the Talend Help Center.
A very simple Job using this feature would look like the one below.
When configuring the model for this Job in TMM, you must provide the context file location in the Context File Directory parameter to allow for the bridge to resolve context variables.
After importing the model, you can see that the DB connection is resolved with expected values.
And you end up with proper stitching.
If the Context File Directory parameter is omitted or wrongly set, the Job model will look as follows, and no stitching will be possible.