Sales by Product report not working

[MattBeserk]

Hi I'm looking for some help with generating Sales by Product reports in Shopify - the net quantity isn't being reported correctly!!!

Using the filters I have just one product selected, but it's showing net quantity sold as only 1 or 2, but then opening that products inventory history there has been roughly 30 sold for the 3 months (and no restocking) 

I've played around with different date ranges and no change, and I've made sure there are no other filters active

any ideas?