This is supposed to be fixed in MC-149443, but it is still affecting the latest release. Steps to reproduce:

1. Cure 2 zombie villagers in a designated area with 13 beds and 13 working sites (all professions)
2. Trade and offer potatoes to meet breeding criteria
3. Stay out in a night to have few zombies scare the villagers, so that Iron Golems can spawn
4. After a few days, you are getting the result of the uploaded screenshots. 13 villagers which is the expected and desired from the bed population, but more than 35 Iron Golems!?!?

During this test scenario you will also meet the other issues reported, like some villagers are acquiring the same job site (MC-150806) and the Iron Golems are stuck on the same spot (MCPE-49607). Please to fix as it is very irritating.