VocabField value cannot be populated with data via subscribe

[andrewbrazzatti]

If you add a subscribe block to a VocabField component, it doesn't update its value.
Example configuration

          class: 'VocabField',
          definition: {
            name: 'project_title',
            label: '@dmpt-project-title',
            help: '@dmpt-project-title-help',
            type: 'text',
            required: true,
            disableEditAfterSelect: false,
           vocabId: 'Projects',
           sourceType: 'mint',
           fieldNames: ['dc_title','dc_description','Identifier',], 
            searchFields: 'dc_title,Identifier', 
            titleFieldArr: ['dc_title'],
            stringLabelToField: 'dc_title',
            publish: {
              onValueUpdate: {
                modelEventSource: 'valueChanges'
              }
            }
          }
        },

Changing the component to a RepeatableVocab allows the value to change.