I have no other plugin that would affect the villagers and their mechanics. When I turned ExtraHardMode off, it worked.

Are villagers considered part of the Animal class now? Iirc that's how the check works. That or breeding in general is disabled for the same reasons animal breeding is disabled.

You can configure this under farming iirc

I think I heard they were making changes in ids. It´s a common breeding in a small village (no mob farm of overcrowding). I gave them a lot of bread, they have their houses and they don't want to breed when EHM is running.

Farming config -

Farming:
    Weak Crops:
      Enable: true
      Loss Rate: 25
      Infertile Deserts: false
      Snow Breaks Crops: true
    Cant Craft Melonseeds: false
    No Bonemeal On Mushrooms: true
    No Farming Nether Wart: false
    Sheep Grow Only White Wool: false
    Squid Only Spawn In Ocean: true
    Buckets Dont Move Water Sources: false
    Animal Experience Nerf: true
    Iron Golem Nerf: true
    Animal Overcrowding Control:
      Enable: true
      # Maximum amount of animals allowed in a small area before they start dying
      Threshold: 2

Hmm, ok, I know EHM does something with animals, I guess it's just EXP farming then - which, in that case, makes this issue all the more strange. Could you experiment with disabling everything in the config and see if the issue is still there?