The JIRA_ISSUES variable is empty in downstream jobs past the first one.

I'm trying to update the related issues as they flow through a series of chained downstream jobs. For Example: BUILD --> QA Deploy --> STAGING Deploy. I'm able to capture accumulated issues from multiple BUILD runs when running the first downstream job (QA Deploy) using the JIRA: Add related environment variables to build in the QA job and referencing the $JIRA_ISSUES variable. However, when I run the next downstream job (STAGING Deploy), $JIRA_ISSUES is empty.

How can I capture the accumulated JIRA issues in a variable in the STAGING job just like it does in the QA job?

STAGING Deploy job configuration: