Digging into this, I'm able to confirm that this is because the internal value for the deal stage label - 'Closed won' is set as 'contractsent'. If you use the following post body:
Currently the internal value 'closedwon' is pointing to deal stage label - 'Closed lost' and since the portal has 5 deals with a deal stage of 'Closed Lost', the return results was 5.
You can check your deals pipeline internal id by going to Settings > Expand 'Sales' > Click 'Deals' > Hover over a certain deal stage > Click the '</>' icon.
Digging into this, I'm able to confirm that this is because the internal value for the deal stage label - 'Closed won' is set as 'contractsent'. If you use the following post body:
Currently the internal value 'closedwon' is pointing to deal stage label - 'Closed lost' and since the portal has 5 deals with a deal stage of 'Closed Lost', the return results was 5.
You can check your deals pipeline internal id by going to Settings > Expand 'Sales' > Click 'Deals' > Hover over a certain deal stage > Click the '</>' icon.