Hands-on Challenge cannot find imported Leads although import completed successfully

Hello, 

I am working on the Trailhead project 

Import and Export with Data Management Tools, step Use the Data Import Wizard.

I successfully imported all 44 Lead records from the provided CSV file using the Data Import Wizard.

•  The import completed successfully. 
•  I received the confirmation email. 
•  All 44 Leads are present in my Trailhead Playground. 
•  They are owned by my user and were created today. 

However, when I click Check Challenge, I always get the following error:

"The 'Lead' records from the CSV were not found. Please check the instructions." 

I also verified that my user language and locale are set to English (United States), but the problem persists.  This was an indication related to this particular module that other people gave as feedback. 

The import file contains also a column Owner with name and surname of the Lead Owner, but no ID. The names and surnames are not even present in the Trailhead Playground, so the Leads were automatically associated to my user because I was the one to import them. 

Has anyone experienced the same issue? Is this a known verification bug? 

#Trailhead  #Trailhead Challenges

#Import Data Challenge  #Importing File