I'm currently running iOS 13.5 (17F75) on an iPhone 11 Pro Max and watchOS 6.2.5 on a S4 Apple Watch and have had no issues unlocking my MacBook Pro (2015 15in) with my watch up thru macOS 10.15.4, but now with 10.15.5 my Watch no longer unlocks my Mac. I can see the "Unlocking with Apple Watch" wording really quick and then it prompts for the password. I've tried turning that option off & on in Settings/Privacy, and I've tried rebooting both my iPhone and Watch. Not sure what else to try other than restoring the watch maybe? Doesn't seem like an issue with the iPhone or Watch, though, as it worked fine on 13.5 & 6.2.5 while on 10.15.4...