ANTI-THEFT SYSTEM light always on while driving on 2003 Chevy Malibu. Car always starts and runs great. How do I turn off the light?

I bought this car used last year and I decided to install a ProStart remote start that I got from a friend brand new. I got everything hooked up properly. I knew that I would need to bypass the Passlock II system but I tried it anyway because I thought maybe the previous owner might have already bypassed it because there was an aftermarket immobilizer installed. When I tried to start the car, it didn't work (obviously it wasn't bypassed previously). I tried to start the car with the key after and ended up having to wait 10 minutes before I could start it.
I drove away to go for lunch and as I was driving, the ANTI-THEFT SYSTEM light went on. When I got home, just out of curiosity, I tried to remote start it again and it worked! It's like the Passlock II disabled on it's own. Its not affecting the way the car starts and it drives fine, but the theft light is always on now and its bothering me.
If the passlock system was disabled, it's supposed to reset and require the key to be relearned when the battery is disconnected but it does nothing. I can unplug the battery for half an hour and when I plug it back in the car starts perfectly without relearning the key, except the anti theft light is still on.