Apple on Thursday issued an unusual "Supplemental Update" for macOS 10.14.6, meant to address problems some Mac owners were having waking their systems from sleep mode.
If not set to happen automatically, the update can be forced by selecting "Update Now" from the Software Update section of System Preferences in the Apple menu. Apple is recommending that all Mac owners install the patch.
The company didn't provide any other information, and indeed AppleInsider is unfamiliar with the cited bugs.
The original version of macOS 10.14.6 was released July 22. That sought to fix graphics glitches when waking a Mac, and it may be that Apple caught exceptions to its work in later testing. The software also made various other bugfixes and closed security vulnerabilities.