Villagers not following schedule

I have been expanding a pre built village I found in survival mode. So far the villagers have been following their schedule of working congregating and sleeping and breeding as i add new beds, however since recently expanding the walls around the village and adding in a couple more beds a number of them have stopped returning to their beds and meeting around the bell. I currently have 24 beds no more than 20 blocks away from one another and I've left the bell at the predetermined centre of the village.