Villager despawn

I have the latest updated ps4 bedrock version of minecraft and still my villagers disappear whenever I am in radius. This happened before the new update and I have conducted experiments and blocked off villagers in various situations and have found that whenever I am within radius of the villager they eventually disappear and do not spawn. How to fix this?

I have also checked chunk borders and find that this makes no difference they still despawn. 

I have cured zombie villagers and they still despawn