Can you please post up a
full and complete VCDS Auto-Scan of your car so we can see all of the exact fault code information.
The intermittent interior sensor fault is a known issue and is seemingly a software bug in some models of the PQ35 body control module. I had my interior sensor module replaced under warranty a few years ago after it completely stopped working. You can see my thread on the Ross-Tech forum
HERE. However, even with a new working one fitted, I still get the "No Signal/Communication - Intermittent" fault code appearing, as do a number of other owners. Even with this intermittent fault code, the sensor does appear to work perfectly OK as tested by me waving my arms around inside the car with the alarm armed, which does set off the alarm.
Also, check the status of the LED on the door. If there is a fault with the system which is preventing the alarm from arming, the LED will remain lit for 30 seconds after arming the system instead of it flashing immediately as should happen if the alarm arms successfully with no faults present. You can see one of my videos showing a fault status
HERE.