When Apple is testing macOS updates with its developers they are using the Combo update, which is a package that contains every single update from the day your macOS version was released. However, what they deliver to the end users is normally an incremental update which only contains the changes from say 10.14.1 to 10.14.2. Unless you have a clean install there is a chance that it will replace files it shouldn’t or, on the contrary, that it won’t replace files that have become corrupted and are now causing problems.
The best thing to do if you happen to experience these problems is to reinstall the update, but instead of using the Software Updates which will only give you the incremental update you use the Combo update. The Combo update will replace all the core system files and give you a completely fresh and up to date macOS install that will hopefully make your problems history.
This is also how you fix your computer if an update was interrupted as the Combo update will restore all missing files and make sure they are up to date.