I don't have that problem but a different one since the update. At the very least, power it off and on and see if that helps. I was having problems where it would lock up when trying to type. I tried clearing the phone's cache, which can sometimes help. To do that you:
Go to Settings>General>Storage> let it calculate and then>Cached Data> OK to clear
I ended up backing up everything to sd, and then factory resetting the phone. Over the years, I have yet to have an Android update pushed to a phone that did not require a factory reset. I resigned into my google account and the apps loaded back. It is smoother and running right now. If you can't track down what app is causing the random vibration, you may want to factory reset it. If you decide to do that, make sure you back up your content before proceeding so you don't lose any pics/music/etc. Good luck.