Same issue exists for me. TouchID for unlock Mac works only once after reboot.
Already tried all workarounds mentioned in previous comments: Removed and added fingerprint
Reset SMC
Nothing helped. Issue is still reproducing.
MacBook Pro (15-inch, 2018)
Aleg0s
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Looks we have solution on reddit)
Steps: Open System Preferences > Users & Groups > Login Options
Click the lock to make changes/enter password
Enable the checkbox for "Show fast user switching menu"
I disabled this to remove an unused icon in my OS menu bar. After I put it back, I tried waking the Mac from sleep and unlocking with Touch ID, then repeated to see if it would work a second time. Looks like this did the trick for me.