We can’t find a active 'Field Generation' prompt template named 'Quick Summary'. Make sure the prompt template API name is 'Quick_Summary'.

Salesforce Support has confirmed that this is a known issue. 

Workaround to complete the challenge

: Creating a new Org again from scratch and repeating the steps fixed the issue.  

To create a new Org using the button "

Create Playground" on the unit, you should create a normal Playground from Profile > Hands-On Orgs

section. 

This will allow you to

Disconnect existing Einstein AI Playground

from your Trailhead profile. 

Once the exisiting Playground is disconnected, you will see "

Create Playground

" button on the unit once again, you can use the same to initiate the creation of new Einstein AI Playground and repeat the steps. 

This has worked for me & I was able to complete the badge.