I have several parameters defined for a Jenkins build through "The project is parameterized".  I created a JIRA trigger with a changelog matcher and also added parameter mapping for a custom field to be used in a later build step.  When I execute the build manually, the Jenkins parameters show up and the build runs.  When it executes via the trigger, the only parameter available is the parameter mapped in the JIRA Trigger.  The other parameters from "The project is parameterized" are not available in the build any longer.