Dataset browsetime problem

Hello, within FortiAnalyzer v5.4.2-build1151, I have a custom dataset which returns the bandwidth and browsing time for top users of social media sites.

It works correctly when I run the 'test' feature within the dataset panel,but when imported in to a report it fails.

Does anyone know why this is taking place? Perhaps there is something in the dataset that is not compatible with Reports ?

Thank you kindly for any help.