Apple this afternoon pulled the 2019-004 Security update.
The first reports coming in are that it's because once the update is installed Macs will Kernel Panic after they wake after going to sleep.
I reported on it here, and also have a work around (upgrade to Mojave) until Apple releases a fix.
https://mrmacintosh.com/apple-pulls-2019-004-high-sierra-security-update-after-kernel-panics//
