This is still an issue in 1.12. I had a fisherman that stopped farming wheat. I tried throwing some seeds at him, but he would not pick them up. I placed him on a hopper with a shepherd and left them there for quite a while. The hopper ended up with 8 bread in it. I tried giving him more seeds again, but he still would not pick them up. I put the fisherman back in the farm and he did farm for a while, but then stopped again quite soon.
Presumably the shepherd converted some wheat to bread and threw it at the shepherd, which allowed him to continue farming for a while, but then he filled up again.
Ahmil Jilani
MC-131071
This is still an issue in 1.12. I had a fisherman that stopped farming wheat. I tried throwing some seeds at him, but he would not pick them up. I placed him on a hopper with a shepherd and left them there for quite a while. The hopper ended up with 8 bread in it. I tried giving him more seeds again, but he still would not pick them up. I put the fisherman back in the farm and he did farm for a while, but then stopped again quite soon.
Presumably the shepherd converted some wheat to bread and threw it at the shepherd, which allowed him to continue farming for a while, but then he filled up again.
Please add Minecraft 1.13-pre6 as well; I've confirmed it there too.
Happens to me reliably on a 1.13.2 singleplayer world that's just about a minute old. Steps to reproduce:
I've attached the world and the log.
Confirmed in release 1.14.1
Confirmed in release 1.14.1
For me, it works if I replace the appropriate "sha1" value in the json with the sha1 of the modified jar.