It happens because of a mismatch in the HTML selectors for those elements.

1. Cart Items Count

   1. Go to Themes in Upsell Cart Drawer and Edit code for your Theme by clicking Actions → Edit code
   2. Expand HTML selectors sections and set your HTML selector for Items Count in Items count field and Save

2. Cart Total Price

   1. Go to Themes in Upsell Cart Drawer and Edit code for your Theme by clicking Actions → Edit code
   2. Expand HTML selectors sections and set your HTML selector for Total cost in Total cost field and Save