If the listing template lacks a basic description setting, the eBay item page will not display the "item description 01" specified in the datasheet.

Solution:
Go to the edited page, click “Body” on the left, select “Basic Description”, drag it to the right.
If you want to delete it, you need to click "Body", then the "Basic Description" part will show a mini trash can icon on its upper right corner. You can delete this part by clicking the trash can icon.
 
Remark:
When creating a new template with the layout “Right Big", the basic description will appear with "1/2 width" by default.

If you delete this original basic description feature and drag a new one into the right side, you must manually select “1/2 width” for the basic description before dragging back to get the fitted result.

Otherwise, the eBay product page will display a text description which is 2 times wider than its left side product image.