Problem

It has been noticed that the usage of a Numbering column and table operations (e.g. adding a new row) in a Sub/Child table can break the data in the Main/Parent Table.

Environment

Reproduced in Confluence Data Center instance version 7.19.2

Steps to Reproduce

• Create a new Confluence DC site version 7.19.2
• Create a page with the storage format as below

  <p class="auto-cursor-target"><br /></p>
  <table>
     <colgroup>
        <col />
        <col />
        <col />
     </colgroup>
     <tbody>
        <tr>
           <th scope="col">Column1</th>
           <th scope="col"><br /></th>
           <th scope="col"><br /></th>
        </tr>
        <tr>
           <td>row1col1</td>
           <td><br /></td>
           <td><br /></td>
        </tr>
        <tr>
           <td>row2col1</td>
           <td><br /></td>
           <td><br /></td>
        </tr>
        <tr>
           <td>row3col1</td>
           <td><br /></td>
           <td>
              <p class="auto-cursor-target"><br /></p>
              <table data-mce-resize="false" data-snooker-col-series="numbers" data-snooker-locked-cols="0">
                 <colgroup>
                    <col />
                    <col />
                    <col />
                    <col />
                 </colgroup>
                 <tbody>
                    <tr>
                       <th class="numberingColumn" contenteditable="false" data-mce-resize="false" scope="col"><br /></th>
                       <th scope="col">subtable with number column</th>
                       <th scope="col"><br /></th>
                       <th scope="col"><br /></th>
                    </tr>
                    <tr>
                       <td class="numberingColumn" contenteditable="false" data-mce-resize="false">1</td>
                       <td><br /></td>
                       <td><br /></td>
                       <td><br /></td>
                    </tr>
                    <tr>
                       <td class="numberingColumn" contenteditable="false" data-mce-resize="false">2</td>
                       <td><br /></td>
                       <td><br /></td>
                       <td><br /></td>
                    </tr>
                    <tr>
                       <td class="numberingColumn" contenteditable="false" data-mce-resize="false">3</td>
                       <td><br /></td>
                       <td><br /></td>
                       <td><br /></td>
                    </tr>
                 </tbody>
              </table>
              <p class="auto-cursor-target"><br /></p>
           </td>
        </tr>
        <tr>
           <td>row4col1</td>
           <td><br /></td>
           <td><br /></td>
        </tr>
        <tr>
           <td>row5col1</td>
           <td><br /></td>
           <td><br /></td>
        </tr>
     </tbody>
  </table>
  <p class="auto-cursor-target"><br /></p>
  

• Publish the page
• Edit the page
• Add a new row in the sub-table that uses the Numbering Column
  • Note that the Numbering column operation is working as expected in the Child table
• Next try to similarly Add a row in the Parent table

Expected Results

• Adding a new row/column in the Parent table should preserve the data and information

Actual Results

• The first column in the Parent table is substituted with numbering information

Workaround

• Refrain the usage of numbering in subtable
• An alternative could be to use Confluence Source Editor to edit the Table data on the page and bypass the Confluence Editor

Notes

• A small recording of the issue reproduced in a local environment is attached
• From further testing, the issue seems to happen only when Collaborative Editing is switched ON. Hope it will help to narrow down the problem and investigation