is this a bug?

Charts Juan.EXCEL.yaml

name: Charts Juan
description: is this a bug?
host: EXCEL
api_set: {}
script:
  content: |
    $("#run").click(() => tryCatch(run));
    $("#run2").click(() => tryCatch(run2));

    async function run() {
      await Excel.run(async (context) => {
        const sheet = context.workbook.worksheets.getActiveWorksheet();

        const mybase65 = context.workbook.getActiveChart().getImage();

        const myChart = context.workbook.worksheets.getActiveWorksheet().charts.getItemAt(0);
        myChart.load();
        await context.sync();

        console.log(myChart.width + " " + myChart.height);
        const mybase64 = myChart.getImage();
        await context.sync();

        console.log(mybase64.value);

        context.workbook.worksheets.getActiveWorksheet().shapes.addImage(mybase64.value)
      });
    }

    async function run2() {
      //using get ASctive chart
      await Excel.run(async (context) => {
        const mybase65 = context.workbook.getActiveChart().getImage()

        await context.sync();

        console.log(mybase65.value);

        context.workbook.worksheets.getActiveWorksheet().shapes.addImage(mybase65.value);
      });
    }

    /** Default helper for invoking an action and handling errors. */
    async function tryCatch(callback) {
      try {
        await callback();
      } catch (error) {
        // Note: In a production add-in, you'd want to notify the user through your add-in's UI.
        console.error(error);
      }
    }
  language: typescript
template:
  content: |-
    <button id="run" class="ms-Button">
        <span class="ms-Button-label">Run</span>
    </button>

    <button id="run2" class="ms-Button">
        <span class="ms-Button-label">using getActiveChart</span>
    </button>
  language: html
style:
  content: |-
    section.samples {
        margin-top: 20px;
    }

    section.samples .ms-Button, section.setup .ms-Button {
        display: block;
        margin-bottom: 5px;
        margin-left: 20px;
        min-width: 80px;
    }
  language: css
libraries: |
  https://appsforoffice.microsoft.com/lib/1/hosted/office.js
  @types/office-js

  office-ui-fabric-js@1.4.0/dist/css/fabric.min.css
  office-ui-fabric-js@1.4.0/dist/css/fabric.components.min.css

  core-js@2.4.1/client/core.min.js
  @types/core-js

  jquery@3.1.1
  @types/jquery@3.3.1