Have you restarted your computer since it has been updated? After the update installed, I noticed things were not acting as they were prior to the update. So, I restarted my computer, and booted it up in Recovery Mode. That is the only way to access Disk Utility, now, unfortunately. Here is an article that will guide you through the process. Don't worry, you will only be using Disk Utility once in there, and you will just check your disk(s) for errors by Choosing "Repair" once into the utility. Let it do its thing, and look for any error messages. Ever since I started using an iMac as my everyday computer, which is a loooong time, I have done the Permissions Repair after each new update, just to make sure everything is in order. It was advice I was given by seasoned Mac users, ,and I have followed it for years.
About macOS Recovery - Apple Support
So, if you are game, just give it a go, then restart your computer from the apple up in the corner.
I hope this helps, good luck!