Yeah, you aren't kidding. I went into APPS, Configure (3-dots at upper right), App Permissions, Phone, Show System (three dots in upper right), scrolled down to home and saw that it was deactivated. Reactivated it and we'll see how this goes.
did you restart the phone afterwards to make sure everything sync's back up?
Several times. I dug deeper into the settings and found "home" disabled in other apps that it shouldn't be. I corrected them and it now seems to be running fine. Battery life does seem to be a bit harder right now. I am letting it go through a full cycle or two and see how that goes.
the battery deal has been an ongoing thing for years..not all phones fully load up how they should out the gate and at times will take a bit longer to fully sync up internally. could take a few charging cycles or restarts..heck you can even back the phone up and reset it. i know that one usually does the trick but its also a pain
To check marshmallow update for your phone:
Read LG G4 Manual for more details.