Ideas
I'm seeing this in my game now, too. Every time I change lots, every time an event begins or ends, every time I switch members in a household, even sometimes for no apparent reason at all, I get reminded of the September sale. It covers notifications so I have to pause, mouse over the cart to clear the pop up, then open my notifications panel to see what happened. It's not just invasive, obnoxious and annoying: it's actual salt in an open wound. Right now I'm actively not buying anything because the DLC I've already paid for is so bugged I can't even use it in regular gameplay. I know about the store. I know about the sale. I'm not buying anything else until you fix what I already bought. Tell your stupid pop up to leave. me. alone!