Originally Posted by
Organ Morgan.
There's always been those whose claims are rejected, or under scrutiny, or failed because of a system error, etc, because it's a gigantic bureaucracy and was that way before the advent of Universal Credit. The case you touched upon is indicative of one of the most common doubts when people are suspected of being shacked-up together while claiming separately, invariably from different households, instead of as a couple at the same address. From reading forums it's often due to someone moving out but continues to have some correspondence delivered to their former abode. You likely know .gov has something known as the General Matching Service that collate a vast amount of data.