NPE : Error processing tag value change - tags json import

Ignition 8.1.23 and before

when I create tags instances of UDT (with json import), I have a few of those error:
I can't figure out which udt def is concerned, (a quite large file is imported) because the gateway logs doesn't mention any tags.

Perhaps @ggross have some ideas of the cause of those error ?

INFO   | jvm 1    | 2023/01/19 12:58:01 | E [t.e.core                      ] [11:58:01]: Error processing tag value change. 
INFO   | jvm 1    | 2023/01/19 12:58:01 | java.lang.NullPointerException: null
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.actors.factories.scaling.ValueScaler$EngLimitEnforcer.checkBounds(ValueScaler.java:381)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.actors.factories.scaling.ValueScaler$EngLimitEnforcer.scale(ValueScaler.java:387)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.actors.factories.scaling.ScalingActorFactory$ScalingActor.processValue(ScalingActorFactory.java:117)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.ExecutableTag.valueChanged(ExecutableTag.java:429)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.actors.factories.value.AbstractValueGeneratingActor.fireValueChange(AbstractValueGeneratingActor.java:73)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.actors.factories.value.AbstractValueGeneratingActor.setListener(AbstractValueGeneratingActor.java:40)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.ExecutableTag.configureActors(ExecutableTag.java:858)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.ExecutableTag.applyPropertyChangesToTag(ExecutableTag.java:631)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.managePropertyChanges(BasicTagDefinition.java:829)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.startPropModel(BasicTagDefinition.java:514)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.activate(BasicTagDefinition.java:980)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.startupInternal(BasicTagDefinition.java:964)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.startup(BasicTagDefinition.java:950)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.AbstractTopLevelUdtTag.configureChild(AbstractTopLevelUdtTag.java:429)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.AbstractTopLevelUdtTag.manageMemberChanges(AbstractTopLevelUdtTag.java:253)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.AbstractTopLevelUdtTag.onSuperMembersChanged(AbstractTopLevelUdtTag.java:174)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.onSuperMembersChanged(TypesFolder.java:589)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.onValidityChanged(TypesFolder.java:536)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.setValidityState(TypesFolder.java:514)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.refreshValidity(TypesFolder.java:430)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.setSuperType(TypesFolder.java:359)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.notifyParentTypeChanged(TypesFolder.java:337)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder$AbstractTypeNode.attach(TypesFolder.java:329)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.TypesFolder.registerComplexNode(TypesFolder.java:114)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.complex.AbstractComplexTagDefinitionNode.startupInternal(AbstractComplexTagDefinitionNode.java:120)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.BasicTagDefinition.startup(BasicTagDefinition.java:950)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.nodes.FolderNode.startup(FolderNode.java:322)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.TagEvaluationManagerImpl.processNewTag(TagEvaluationManagerImpl.java:577)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.TagEvaluationManagerImpl.processEditInternal(TagEvaluationManagerImpl.java:407)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.runtime.TagEvaluationManagerImpl.processEdit(TagEvaluationManagerImpl.java:321)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.TagProviderImpl.saveTagConfigInternal(TagProviderImpl.java:813)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.TagProviderImpl.lambda$importTagsAsync$25(TagProviderImpl.java:1140)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at com.inductiveautomation.ignition.gateway.tags.TagProviderImpl.lambda$exec$5(TagProviderImpl.java:462)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
INFO   | jvm 1    | 2023/01/19 12:58:01 | 	at java.base/java.lang.Thread.run(Unknown Source)

Based on where the error is occurring, I think it will be occurring on a tag with a Scale mode set (likely with a clamping mode set) that somehow is getting a null qualified value. I know that is pretty vague, but hopefully that narrows the potential culprits a bit.

Garth

Thanks, I will try to only import few tags candidate based on your track.