Magic columns around sent and received emails determine what's "sent" and "received" by the From and To fields in an email. If you're sending and receiving emails through an alias, it's likely that Streak is unaware of that alias and it's distorting your data.
There's a workaround for this, but it's only available if Guest Mode is enabled for your Team and your pipelines. To enable Guest Mode for your Team:
Click the Streak menu item in Gmail's top, righthand menu bar.
Select the Manage Billing and Teams icon in the sidebar on the right.
Click Allow Guest Mode:
Now you're ready to add a guest user to your pipeline! Bonus: Guest users are free pipeline users and you will not be charged for adding your email alias as a guest.
Click on the name of your pipeline on the lefthand sidebar in Gmail
From the pipeline toolbar, select the Shared or Private button on the top, right side.
Click into Advanced.
If Guest Mode is off, turn it on by clicking enable in the bottom right corner.
Down in section "C", select the Add button to the right of Guests for just this Pipeline and add your alias an a guest user.
Streak will now recognize emails sent/received from this alias as part of your pipeline's users. Your emails sent from this alias will register as sent/received properly and your magic columns should soon be updated!