Hi Harlin.
The list records encapsulates items if you perform any ajax operation on the list. When you use the ajax refresh with a list records, you can refresh just a single item on the list, by using the Row Number property of the ajax refresh. When you use the ListAppend or ListInsert with the record list, this also affects a single item on the list.
For those operations to work, OutSystems needs to include a markup to delimit the items. That's why the <span> is added.
I am not aware of a workaround that does not involve removing the ajax refresh code, or maybe refreshing the whole list instead of a single item.