In the Trailhead module Data Modeling, Unit two, Create Custom Object and Fields, the challenge section is missing.  Whats even more odd is that I was sure  I had already completed it.  

I've tried different browsers but the Challenge for the Custom Objects and Fields is not visible.  (On Trailhead for the Admin Beginner)  Furthermore, the feedback link on this page does not work.  As a result, I cannot complete this module as it remains stuck at 75% even though I've finished everything before and after it.  Please advise so I can get this marked as complete?

The URL in question is:  https://trailhead.salesforce.com/en/trails/force_com_admin_beginner/modules/data_modeling/units/creating_custom_objects_fields
 

I've tried three different browsers, as well as logging out and logging back in. There is no challenge at the bottom of Create Custom Objects and Fields in the Data Modeling Trailhead. Clicking the bookmark on the right hand list does not work either. Is this a bug?

In the Trailhead module Data Modeling, Unit two, Create Custom Object and Fields, the challenge section is missing.  Whats even more odd is that I was sure  I had already completed it.  

I wanted to solve the challenge on "Create Custom Objects and Fields" section but challenge doesn't display. Instead i get "Remember, this module is meant for Salesforce Classic. When you launch your hands-on org, switch to Salesforce Classic to complete this challenge" information and despite switching to Salesforce Classic i can't see the challenge. Any solutions?