This is how it will be working now. You can always disable the events completely.

That was the sense I was getting from the Shop FAQs board :p

https://subeta.net/forums.php/read/854270 "The new shop system notifies you whenever you make a sale. So, if you sell 20 things, you'll get 20 events. This can get annoying to some, so here's how to turn off those notifications."