The Lists app for Microsoft teams has a user interface bug pertaining to retention labels. Whenever applying a label to a new item, it creates a redundant "apply label" column. The same issue has been described here: https://techcommunity.microsoft.com/t5/microsoft-teams/lists-tab-incident-template-apply-label-everywhere/m-p/1634554/highlight/false#M71079

This bug does not occur in the Lists web app, nor in SharePoint, but only in the Lists for Teams application (both Teams web app and Teams desktop client), when creating a new item.