The plugin shows correct timestamp when looking at the [Console Output:

2019-10-03 01:28:35 Started by upstream project "10.7_release_pipeline" build number 89
2019-10-03 01:28:35 originally caused by:
2019-10-03 01:28:35 Started by timer
2019-10-03 01:28:36 Running in Durability level: PERFORMANCE_OPTIMIZED
2019-10-03 01:28:42 [Pipeline] Start of Pipeline
2019-10-03 01:28:42 [Pipeline] properties
2019-10-03 01:28:43 [Pipeline] timestamps
2019-10-03 01:28:43 The timestamps step is unnecessary when timestamps are enabled for all Pipeline builds.
2019-10-03 01:28:43 [Pipeline] {
2019-10-03 01:28:43 [Pipeline] library
2019-10-03 01:28:43 WARNING: Unknown parameter(s) found for class type 'jenkins.scm.impl.subversion.SubversionSCMSource': ignoreExternalsOption
2019-10-03 01:28:43 Loading library templates@branches/rel/10.7.0.x/build/change-management/jenkinsfiles/templates

But when looking at the same build instance using [View as plain text] the timestamp is wrong:

[2019-10-02T22:28:35.925Z] Started by upstream project "10.7_release_pipeline" build number 89
[2019-10-02T22:28:35.925Z] originally caused by:
[2019-10-02T22:28:35.925Z] Started by timer
[2019-10-02T22:28:36.043Z] Running in Durability level: PERFORMANCE_OPTIMIZED
[2019-10-02T22:28:42.245Z] [Pipeline] Start of Pipeline
[2019-10-02T22:28:42.703Z] [Pipeline] properties
[2019-10-02T22:28:43.191Z] [Pipeline] timestamps
[2019-10-02T22:28:43.191Z] The timestamps step is unnecessary when timestamps are enabled for all Pipeline builds.
[2019-10-02T22:28:43.192Z] [Pipeline] {
[2019-10-02T22:28:43.404Z] [Pipeline] library
[2019-10-02T22:28:43.416Z] WARNING: Unknown parameter(s) found for class type 'jenkins.scm.impl.subversion.SubversionSCMSource': ignoreExternalsOption
[2019-10-02T22:28:43.448Z] Loading library templates@branches/rel/10.7.0.x/build/change-management/jenkinsfiles/templates

The timestamper is enabled for all pipeline build and has the following formating: '<b>'yyyy-MM-dd HH:mm:ss'</b> ' which appears correct in the [Console Output] but not in [View as plain text]

We have the following java argument added to our master configuration: JAVA_ARGS="-Dorg.apache.commons.jelly.tags.fmt.timeZone=Europe/Sofia"

The hardware clock of the VM on which the master is hosted ouputs correct timing as well:

sudo hwclock --show

Thu 03 Oct 2019 10:03:11 AM EEST -0.355352 seconds

date
Thu Oct 3 10:04:14 EEST 2019

I wonder where is the wrong timestamp read from?

Perhaps, if I knew I would be able to work around the issue by changing some system settings. Browsing the console text with correct timestamps is quite important especially when you have big outputs in general...