If you need to use products tables from the deal or lead, you need for html-table with specific structure
<thead>
Headers
</ thead>
<tbody>
Products rows
</ tbody>
<tfoot>
Footer
</ tfoot>
A html-table with a required structure can be added by drop-down menu Paste value -> Products -> Example of product table


If you have added a table with products (or copied from the other source) you should to modify it via html source and made compatible structure.

Important: <tbody></tbody> should contains only one row. It'll be copied and filled by data as source has rows.