NullReferenceException when opening RuntimeDecoder inspector for the first time

[Varneon]

After opening a new RuntimeDecoder's inspector for the first time, NullReferenceException is thrown:

NullReferenceException: Object reference not set to an instance of an object
AvatarImageReader.Editor.RuntimeDecoderEditor+<>c__DisplayClass29_0.<CreateInspectorGUI>b__8 (UnityEngine.UIElements.ChangeEvent`1[T] a) (at Packages/com.miner28.avatar-image-reader/Editor/RuntimeDecoderEditor.cs:182)
UnityEngine.UIElements.EventCallbackFunctor`1[TEventType].Invoke (UnityEngine.UIElements.EventBase evt) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.EventCallbackRegistry.InvokeCallbacks (UnityEngine.UIElements.EventBase evt) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.CallbackEventHandler.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.EventDispatchUtilities.PropagateEvent (UnityEngine.UIElements.EventBase evt) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.DefaultDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.EventDispatcher.ApplyDispatchingStrategies (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, System.Boolean imguiEventIsInitiallyUsed) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.VisualElement.SendEvent (UnityEngine.UIElements.EventBase e) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEngine.UIElements.BaseField`1[TValueType].set_value (TValueType value) (at <b6a7e1825c0b45d3b0729282e86cc687>:0)
UnityEditor.UIElements.BindingExtensions+SerializedManagedEnumBinding.Release () (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.RemoveBinding (UnityEngine.UIElements.IBindable bindable) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.DoBindProperty (UnityEngine.UIElements.IBindable field, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper obj, UnityEditor.SerializedProperty property) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.BindPropertyWithParent (UnityEngine.UIElements.IBindable field, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.UIElements.BindingExtensions+SerializedObjectUpdateWrapper objWrapper, UnityEditor.SerializedProperty parentProperty) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.BindingExtensions.Bind (UnityEngine.UIElements.VisualElement element, UnityEditor.SerializedObject obj) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.InspectorElement.PartialReset (UnityEditor.SerializedObject bindObject) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.InspectorElement.AssignExistingEditor (UnityEditor.Editor value) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.UIElements.EditorElement.Reinit (System.Int32 editorIndex) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.InspectorWindow.ProcessEditorElementsToRebuild (UnityEditor.Editor[] editors) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.InspectorWindow.DrawEditors (UnityEditor.Editor[] editors) (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.InspectorWindow.RebuildContentsContainers () (at <a259d3c004024353a2c217da97495055>:0)
UnityEditor.InspectorWindow.RedrawFromNative () (at <a259d3c004024353a2c217da97495055>:0)