When creating commerce creation the content is automatically set to have an expiration date 10 years in the future when the expiration was left blank. Further editing content to remove the expiration shows the same results.
This is actually intended functionality within the commerce items. The way that the commerce data layer is designed will require an expiration date. If this expiration is not specifically set at any point the system will have the content expire in 10 years to replicate the behavior of omitting an expiration date.