Yes. It breaks root and you lose custom recovery
From the xda-dev thread: "So I was not paying enough attention today and I let my phone upgrade to 9.18.94. The phone had been previously rooted and I also had a custom recovery ROM installed. The OTA update seems to have gone pretty smoothly but at this point I think I've lost all of the "custom" stuff I had done - namely the recovery ROM and the root access. I knew this was likely to happen but unfortunately it slipped my mind before I did the upgrade."