Zoho Reports Not Grouping from Subforms

Zoho Reports Not Grouping from Subforms

I have created reports from a subform. We have a budget from a standard field, and the bills added to a subform. I've summarised the bills in a field. 
In edit mode, the bills are joined per supplier, which is what we want. But then it converts and separates/duplicates each bill. 
How can I make these reports group the bills by the Supplier?


EDIT: it looks like the reports are not updating automatically. They have always done so until recently. This may be why the reports are not changing.