Mac doesn't unlock with Apple Watch after Watch is unlocked

I use my Apple Watch to unlock my Mac. I tap the keyboard and it unlocks.

Sometimes my watch is locked and I get the message that the Watch must be unlocked to unlock the Mac. All good.

I unlock my Watch, and nothing happens. Do I have to wait a minute or two for the login screen to reset before I can use the watch? Is there any way to tell it to try again with the Watch?

Thanks!