Villagers keep breeding

Villagers keep breeding more than number of beds in village.

Breeding has stopped once, but start breed again triggered by a trade with villagers. In the meantime, I was don't put the new bed in village.

The breeding continues, eventually over 60 villagers against 23 beds spawned.
As a test, I kept watch over villagers breed themself. Then the game has crashes.

 

FYI,That villages features

 - Savanna biome.

 - There is the end portal in the basement.

 - Generated by v1.11.0.

 - some villager does reached max level of trade.

 - First villager is cured zombie villager.