Apple has released an updated version of macOS Mojave 10.14.5 for 2018 and 2019 for MacBook Pro models (15-inch) that feature a T2 security chip. It can be downloaded via the “Software Update” section of System Preferences on the laptops.
Apple release notes say “the MacBook Pro Supplemental Update addresses a firmware issue affecting 15-inch MacBook Pro computers with T2 Security Chip, and is recommended for all users.”
