When I upsert the same catalog item more than once, the second upsert deletes the description from the item_data node. Does anyone know why or how I can prevent this from happening?
The description field in the catalog is deprecated. We recommend that you use the description_html field instead as that will be the supported field moving forward. 
I am sorry, I am using description_html
Okay, great! This is an issue and the team is aware of this when upserting an object more then once. I’ll be sure to reach out with any updates.