I have a job that starts builds of several other jobs. These builds sometimes where started with some paramers that where null by mistake (bug in the script of the upstream job).
Then global env vars where missing for one of the downstream jobs (not all of them).

Pipeline script of the downstream job:
paratext= "params: \n"
params.each

println paratext

println "env.TOOLS_BUILDSTART: "+env.TOOLS_BUILDSTART
def envVars = Jenkins.instance.getGlobalNodeProperties()[0].getEnvVars()
println "envVars: "+envVars

Output when started correctly:
Replayed #115
Running in Durability level: PERFORMANCE_OPTIMIZED
[Pipeline] echo
params:
node=null
BUILD_CLEANUP=false
VERSION_OVERRIDE=
GERRIT_TOPIC=JenkinsTest_ToolsBuildpy
TOOLS_REFSPEC=refs/changes/29/15929/4
GERRIT_REFSPEC=
GERRIT_PROJECT=

[Pipeline] echo
env.TOOLS_BUILDSTART: /opt/ToolsBuildpy/JenkinsTools/build_start.gvy
[Pipeline] echo
envVars: [TOOLS_BUILDSTART:/opt/ToolsBuildpy/JenkinsTools/build_start.gvy, TOOLS_REFSPEC__unused-usingmaster:dummy]
[Pipeline] End of Pipeline

Output when started with null parameters:
Replayed #120
Running in Durability level: PERFORMANCE_OPTIMIZED
[Pipeline] echo
params:
node=null
BUILD_CLEANUP=false
VERSION_OVERRIDE=
GERRIT_TOPIC=JenkinsTest_ToolsBuildpynull
TOOLS_REFSPEC=refs/changes/29/15929/4
GERRIT_REFSPEC=null
GERRIT_PROJECT=null

[Pipeline] echo
env.TOOLS_BUILDSTART: null
[Pipeline] echo
envVars: [TOOLS_BUILDSTART:/opt/ToolsBuildpy/JenkinsTools/build_start.gvy, TOOLS_REFSPEC__unused-usingmaster:dummy]
[Pipeline] End of Pipeline