Based on the details you’ve given, one possibility could be due to the nature of your events. The “login” event (where your “customer_type = Webonly” comes from) and the “purchase” event are two separate instances. When you try to apply these filters together, it might be looking for a scenario where both parameters are occurring at the exact same event, which in this case is not possible. Therefore, it returns with “no data”. You can use these filters individually because they’re able to find corresponding events separately. However, when used together, they can’t find any combined events matching both conditions. You may need to adjust your tracking setup or analytic queries to get the desired result.