Unsure if this works for others. I just tried toggling this and smart lock works now. In Secure lock settings > turn off 'lock instantly with Power key' > Lock your Phone and wait 5 secs or more > Unlock phone (There was a 1-time notification saying its unlocked becos of Smart Lock). It should be not locked and just swipe the screen to get to Home Now you may turn back on 'Lock phone instantly' and Smart Lock still works.
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