When Creating New views using the “Standard View” option, SharePoint sets the new list to a “Tabular View” by default. This means that individual check boxes appear to the left of each Flex item displayed in the list. The check boxes typically are not desired in a Flex list view.
Disabling the Tabular View function can be done by scrolling to the “Tabular View” section when the view is created. Click the box to remove the checkmark.