Your settings look good. I've seen another post about a similar problem. What helped was recreating the Abandoned checkouts customer group.
The only idea that comes to my mind is to try contacting Shopify support, as the discount you set up should already work. I checked the same discount settings in my test store, and they worked as expected.
Another suggestion, if you are open to employing an app, is to use Personal Discount to generate unique discount codes for your abandoned cart emails. Each discount code will be tied to the customer who abandoned their cart. You can also make the offer time sensitive, for each customer individually. For example, you can specify that the discount codes are valid for 24 hours only. I'm the developer of Personal Discount. I'll gladly help you with integrating it with your current cart recovery email.