Door Lock Issue, Viper 4105v, 2012 Yaris Sedan

2012 Yaris SEDAN (so wiring is from 2011 per directechs). No immobilizer (so obviously no immb bypass module). No factory alarm. Customer had the Viper 4105 remote start/keyless installed ~9 months ago. Everything worked great until about a week ago. Now the Viper lock function doesn't work. Unlock and remote start work 100% of the time. If you hit Viper unlock, then Viper lock, the lock function does indeed work. But if you wait a few minutes, the lock function will not work anymore. While the Viper lock is inop, the factory lock switch works fine and the door key cylinder works fine (turn key twice to lock to power lock all doors). Using these, to even unlock, does not then allow the Viper lock function to work. You have to press the Viper unlock button, then Viper lock to get it to work. Shouldn't be anything special. It's just Viper lock/unlock wires to the driver's kick to tag factory arm/disarm or lock/unlock. It used factory arm/disarm for the ~9 months, but I tried moving it to the actual lock/unlock wires, no change. Tried diode isolating to trigger lock and arm at the same time. No change. Swapped in a new brain, antenna, and antenna wire. No change. Ground for the brain is solid. Solid bare shiny metal in the driver's kick.

Oh and customer states that no work has been done to the vehicle. I even ensured him that I'm not looking to point fingers to somebody/something else, I'm just trying to fix your problem. He swears nothing has changed.

The viper lock output is only one time. If it is locked with viper and you press lock again, it does not output the locks but flashes the parking lights. If you unlock then lock again, you will get an output. It only outputs once. If you keep hitting lock, nothing will happen. It is like this all the time, the 4103 series all do the same, Avital Python etc.