A few questions about Drop

I signed up for Drop after reading Fishering's 13 Ways to Save Money Passively

My first issue is that the app crashes whenever I scroll down a bit (around "Footwear" or so). I'm using an Android 6.0.1 phone. Does anyone else have this issue?

Next...

For those of you who don't know what Drop is, Drop is a passive loyalty program that allows you to choose 5 popular stores where you'll earn cash back (automatically) at as soon as you shop at them (both online or in store). Here are just a few of the stores you can pick from: Walmart, Macy's...

I buy groceries at Wal-Mart often so I'd like to choose that as one of my stores. However, when I go to "Food and Grocery" and select Walmart, it has a big green "SHOP NOW" button that brings me to WalMart.com. Is it not possible to use Drop with in-store WalMart purchases anymore?