Lunar New Year Workout Challenges

Best advice is

First force restart the Watch 

i.e. press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo. 

 Then, although it may seem irrelevant, while it is restarting Force Restart the paired iphone   Force restart iPhone – Apple Support (UK) 

If the badge does not appear wait a few days becausevthey can spontaneously appear and the next step us a pain,

it is still misbehaving... Unpair and set up again

 Unpair and erase your Apple Watch – Apple Support (UK) 

and then 

Set up your Apple Watch – Apple Support (UK)

You may also want to make sure the software on the watch and iphone  are up to date. 

Update your Apple Watch - Apple Support 

Update your iPhone or iPad - Apple Support 

If you've completed that troubleshooting and the issue is still not resolved, Contact Support. 

 Click here > Contact - Official Apple Support

or phone numbers  

Click here > Contact Apple for support and service - Apple Support

No there should be no delay. I got it as soon as I had completed whatever the requirements were - I didn't even know about it til the badge showed up.

Mine says I did one 20 minute workout between Jan 20 and Feb 5

In A

Look further down in Limited edition awards

I read elsewhere that they can spontaneously reappear. Is why I hoped a restart would suffice.

Thats great, glad I could help.

Good luck.