When I'm choosing one value from PT_MULTI_SELECT parameter and then applying a filter my previous selection is gone

 
properties([
parameters([
[$class: 'ChoiceParameter',
choiceType: 'PT_MULTI_SELECT',
omitValueField: true,
description: 'Package/s to be added for example: "cosm-mon, cosm-cli, ulc-mulpi"',
name: 'NEW_PACKAGES',
filterable: true,
script: [$class: 'GroovyScript',
fallbackScript: [
classpath: [],
sandbox: true,
script: 'return ["ERROR"]'
],
script: [
classpath: [],
sandbox: false,
script: """
return ['A', 'B', 'C','D',E, 'F', 'G']
""".stripIndent()
]
]
]
])
])