So I am trying to breed villagers while I finish building my castle (their 'future home'), but with no luck. I've had success with this infinite villager breeding system before but it does not seem to be doing the trick this time around. I have a farmer with two others in the pen on the left, and a boat-trapped villager within 8 doors on the upper right. I put in the door-less structure as a wild guess since there was one or two present in my last setup. I've also checked for stray doors/beds w/in a 128-block radius and it's all clear. I've also traded with each multiple times, fed them plenty of food, and observed several instances of 'willing' particles emit from the villagers.
Last time it didn't take much time to go from 'willing' to seeing hearts, but now they're being stubborn. Any help?