With Wagestream, you have access to earnings right up until payday so for anyone who is on an Arrears schedule like yours, there will always be a date range in which you have access to wages from two pay periods at once: the previous pay period (as you've not been paid for this yet) and the current pay period (the one we're in right now). We refer to this as the Arrears Zone.
Any streams performed during this Arrears Zone may be accessing earnings from either your previous pay period, the current pay period (so will be carried over to your next paycheck), or both (split across paychecks then carried over). Which pay period(s) your streams come from will depend on how much you have earned at the time of streaming:
More details of how this breakdown happens can be found on the balance calculation page by tapping the ℹ️ icon in the Track header.
You can check when an individual stream will be reconciled by selecting Streams on the Track page of the app, tapping on the stream you would like to view, and then scrolling to Settlement details.