That's just how the supermarket pharmacies work -- at least with Superstore and Safeway. When the pharmacy is closed, they pretty much lock up everything in the over-the-counter section as well.
That said, ever since COVID, it seems to me that the supply of infant & children Tylenol and Advil has been forever unstable. Sometimes they have them, and sometimes they don't. Usually when I need it, they don't have any in stock. And so I buy it in advanced when it is available, only to have it go past the expiry date the 2nd or 3rd time when we need to use it.
