After the system update, there's a delay in locking the phone.

[Henryfehr91]

Certain apps don't work as well either, after the update. 

[RedDogRabbit]

Play System Update, or Security Patch Update? 

I always Boot into Recovery after every Security Patch Update & Wipe Cache. 

See if that works for you. 

[Henryfehr91]

It's the software update, otherwise known as system update.
I'll try that, thanks