[JENKINS-47370] Unable to override global envs after update to 2.1.4

We have a global setting of JIRA_URL=jira.acme.com

In some jobs we override this in the "Prepare an environment for the run" section to JIRA_URL=jira-staging.acme.com

After upgrading to 1.24 this stopped working. The effective value as seen in shell scripts is jira.acme.com

Setting the value in a "Inject environment variables" build step also has no effect.

The only thing that has an effect is to set the value inside the shell script.

is duplicated by

JENKINS-53229 Regression: Variables set in generateEnv are unset by the SECOND envInject

JENKINS-53213 Adjustments of ENV variables created by the EnvInject plugin are not carried over to new shell steps in a freestyle build.

relates to

JENKINS-14437 envinject fails to "really" set/override build parameters

JENKINS-47364 Existing variables not being substituted in Properties Content

links to

CloudBees Internal OSS-2517

Jenkins