Where do the figures come from?
The Android app detects calls, sends the texts and passes each event to your client space. So the dashboard shows the same thing as the phone's history. If a counter stalls while you know you missed calls, look at the Devices block first: a phone under battery optimisation, common on Samsung, Xiaomi, Oppo or Huawei, may stop sending updates. The setup guide in the app shows how to exclude it. Once the phone is active again, pending events come through and the charts fill in.