Adobe VIPE CC Named Licences - multiple licenses per user

I have a problem that so far, no one has been able to recreate or understand. We purchased named licenses for all the students at our school, but the problem we have now is that 1056 users use 1096 licenses. If I download the 'license-status-report', I see that below some usernames, there are up to 5 lines where only the columns 'Product', 'Product profile name', 'Product delegated' and 'Product provisioned' are filled in. 'User name', 'First name', and 'last name' are empty. And if I add those up, then those blanks amount to those 40 lost licenses... How is this possible? Has anyone experienced a similar thing? 

Thanks for your help!