Daewoo Kalos anti-theft malfunction?

Background:
Years ago i had an issue with airbag warning light constantly lit. Took car for maintenance and all the told me is to fix it they rerouted it.

Current issue:
After that rerouting my car has been wonky and weird.

DOOR UNLOCK and ANTI-THEFT MODE DEACTIVATION
1. Press and release the door unlock button on the transmitter.
• The LED on the transmitter will flash once. WORKS!
• All the doors unlock. WORKS!
• Hazard warning lamps flash twice. WORKS!
• Anti-theft mode is deactivated. UNKNOWN!

DOOR LOCK and ANTI-THEFT MODE ACTIVATION
1. Close all windows.
2. Turn the ignition key to LOCK and remove the key.
3. Have all passengers exit the vehicle.
4. Close all doors, hood and trunk.
5. Press and release the door lock button on the transmitter.
The LED on the transmitter will flash once. WORKS!
• All doors lock. WORKS!
• Hazard warning lamps flash once. DOESN'T WORK!
• Anti-theft mode is activated. DOESN'T WORK!

If hazard lamps flash once and anti-theft led (red) starts blinking in dashboard. After 10-15min hazard lamps WILL start flashing for several seconds, again and again and again until battery is flat.

Changed battery in FOB, tried the following:
Manually unlock doors.Sit in car with doors closed, turn ignition key to [ON], hold remote [LOCK] button for 2 seconds to sync. Didn't work, locks didn't cycle at all, or other indicators.

Manually unlock doors.Sit in car with doors closed, turn ignition key to [ON], hold remote [LOCK]+[UNLOCK] button for 15 seconds to sync. Didn't work, locks didn't cycle at all, or other indicators.

Even tried to do [ON]->[OFF]->[ON], in increasing times but nothing.

Issue still persist. My conclusion is that either one or several central locking systems sensors might be malfunctioning or anti-theft system is not working properly after that rerouting shit. Thing is there have been several times that the engine in mid drive hick-ups and every time one or both engine check/abs light lit up. Which sometimes go away after sometime or take car for maintenance to reset error codes.

Oh right, two times this issue has drain my car battery totally flat, so badly it had to be replaced. While in maintenance last time when checking for any active battery drainage sources, they used only key to open and close doors. They didn't find any sources that would drain car battery flat.
Without driving battery could go flat in 2-3 weeks. Conclusion, issue has to be FOB related because every time battery went flat i had tried to use only FOB to unlock and lock car.