Instead of blending, please try to do a full outer-join and see if that helps.
So there’s no way to fix this by blending?
Ideally, you have to ensure that all the combinations exist in both the Salesforce data as well as the quota data by team. But since that's going to be a problem, it's better to do a join. You can attempt a partial blend by using only the sales team or month for blending, but that could result in incorrect outputs.