I had no modifications on my phone at all; it was stock everything. I wanted to install Hyperdrive on the phone so I went through the usual steps.
2) Flash CWM
3) Create nandroid back up within CWM
4) Flash Hyperdrive ROM
I used Hyperdrive for a few weeks, but then I wanted to go back to stock, so I restored my backup. I was on stock for another few months and then OTA updates started coming in. I know that I cannot install OTA updates with a custom recovery. (I assumed I still had CWM)
So here is the thing...I thought that the backup I made was in the state of being rooted with CWM and stock ROM. So I assumed that after restoring the backup, I was rooted with CWM and stock ROM. So I double checked and found that I was not rooted and I had stock recovery installed. Does anyone know how this happened?