The software if designed to NOT allow a waiver add on Sunday after the previous week maximum has been reached. This is a flaw...
Removing a flaw found in week-start waiver adds after Sunday games have egun.
Walter Kasper commented
This is indeed a flaw - he's not asking about when the acquired player can START, he's saying he can't create a waiver claim on Sunday night he is out of adds for the week. In previous seasons, you could create a waiver claim on Sunday because the claim is processed Monday when adds reset.
You need to pick up waiver players on Saturday night to use them the following week.
This is not a flaw and will not be corrected.