Since updating from 2.8.1 to 2.9.0 the JobDSL for many of our jobs has begin failing with the following error:
ERROR: (XXXscript.groovy, line 88) the following options are required and must be specified: customBuildName, overrideBuildName

By definition these fields are optional, this is not expected;
To work around this we have had to update a number of job configurations as follows, since the upgrade:
artifactoryRedeployPublisher {
customBuildName(null)
overrideBuildName(false)
...
}