UPDATE

I've found out the cause.

Afterall, "Ghost Villagers" are not the cause of this bug. They are actually Cats and Iron Golems that have been converted between previous versions and MCPE 1.11. Apparently, they can claim beds and work stations.

----------------------------------------------------------------

After the MCPE 1.11 update, I began placing beds and work site blocks for villagers that I've had since MCPE 1.9. Right off, I noticed that not all the villagers were gaining professions, despite placing the same number of work sites & beds as how many villagers there are. However, every time I placed a bed/work site, the green particles would show as if a villager claimed it. It can't be any villagers outside of the village as there are no nearby villages to be seen.

I've created a test copy of the world and killed all my villagers, leaving only one alive, and this problem still happens where beds and work sites are claimed, but the only living villager doesn't seem to be the one claiming them as the particles don't spawn around him. It wasn't until I placed 9 beds and work sites when the villager would actually claim one

While testing this over and over, I've noticed green particles spawning in random places every now and then as I placed beds/work sites that got claimed by their unknown owner. With this, I've concluded that perhaps it's a bug where "ghost villagers" (Villagers that possibly died in previous versions or disappeared within the transition to newer versions) are claiming these blocks. Perhaps their entity ids still exist within the world and are claiming the beds/work sites? Besides that, I'm clueless as to why these blocks are being claimed without any other villagers around.