Hi,
The only explanation I’ve got – some order items (i.e. products) do not have the cost entered. Even if an order has profit calculated, it may be that some items don’t have cost set. For example, let’s say we have an order with a total of $100. Let’s say this order has two items: Product A and Product B, both sold for $50. Now if you have only set cost for Product A (let’s say $30), then the order profit will show $20, so that can produce a mismatch.
Again, if I could log in, I would be able to tell exactly what’s happening. I would start by checking reports day by day (i.e. instead of “This month”, I would start checking “2020-03-01 – 2020-03-01”, “2020-03-02 – 2020-03-02” and so on, until I could see a mismatch, then I would check each order for that day.