Why is the play store displaying same app twice under the My apps section
The publisher of this app may have changed their package name when updating the app. Usually, apps have the same package name for its entire lifetime, which is how the phone knows to update a current app instead of installing a new one. If this is the case, you should uninstall the old app. The quickest (and easiest) fix is to uninstall both and reinstall the latest version. Provided the app's package name doesn't change again during the next update, this should solve your issue.