Apple series 3 watch does not unlock iMac

Setup my Apple Watch Series 3 today. Took my iMac out of sleep and noticed it was not unlocked from my watch.

I go to Security & Privacy and under "Allow Apple Watch to unlock our Mac" I see a check box for my series 1 watch and a checkbox for my series 2 watch, but there is no checkbox for my Series 3 watch.

Prior to setting up my Series 3 watch the Series 2 watch has been working fine unlocking my iMac.