Did you by any chance upload the submissions using the QuickSubmit plugin? There is a known bug that has been reported where the licensing information is missing from submissions that were added using QuickSubmit.
There is also a known issue where the license details disappeared from article pages after upgrading to OJS 3.2. There is a workaround suggested in this forum post: License disappears after upgrade to 3.2.1 - #4 by IOPNdev
In both cases you can also try unpublishing and republishing the issue or article to see if the license information appears.
I hope this helps.