villagers Dying to suffocation

On my world I had a villager trading hall when all the villagers woke up the next morning alot of then started Suffocating and died when i was looking around to see what villagers had died i noticed that the only villagers that had died were villagers that had not had full block work stations (lecterns, brewing stands and grindstones to list a few) . And the place the villagers suffocated at was the same block the work station was on. 

i don't know what happened but i think that the villagers wanted to wake up on a block then It wanted to wake up on the work station block and since the work station wasn't a full block it woke up and suffocated there