Sometimes, when a villager "shares" food with another villager, the food item is immediately picked up by the villager that threw it. This can prevent villager "breeder" contraptions from working well, unless both villagers already have sufficient food in their inventory.

To reproduce:

1. Spawn 2 villagers near pathable beds (beds may be optional)
2. Drop 24+ carrots (as a single entity works best) near the villagers, which one of them will pick up
3. Keep both villagers in close proximity
4. The villager that picked up the food will attempt to "share" food with the other by throwing food entities at the latter
5. The thrown food entities will often get picked up by the same villager who threw them, depriving the second villager of the necessary food to begin the breeding process

While this issue could be overcome by simply overloading both villagers' inventories with food, that is inefficient and inelegant.

My suggestion would be to add a "pickup cooldown" to any villager who is sharing food that would prevent them from picking up food at the same time they are throwing it.

I've attached a video of the process in action. I also have the world save that the video came from, if that might help