Further testing:
1) Create a valid villager house
2) Place a villager outside of the house in a glass cage where he cannot move
3) Set time to night
Error message received = Using : vm@eaa1ca4
1) Kill previous villager
2) Place new villager inside house
3) place block in front of the door to ensure he does not leave
4) Still night
Error message received = Not using : vm@eaa1ca4
In both of the above cases, the error stops as soon as it is day
In both cases, if I remove the door and replace it, the error message changes, presumably linked to the ID of the door itself
Other unusual behaviour:
I note that at night my villager did not want to go indoors on his own. After the above tests, I removed the block keeping the villager in his house and he immediately left the house. He then stayed out for the duration of the night.
I then reset to night time again and spawned a villager. The villager fled from the zombie but made no attempt to enter the house.
I've been experiencing this for the last two snapshots. Finally I decided to try taking out the most likely culprits. For me it seemed to be related to my command block contraptions. I started up my world without the region file that the contraptions are in, and the world worked fine; the errors stopped. I put that region file back in and the errors came back. I then removed the contraption entirely and the errors stopped.
Couple things could have gone wrong here:
1) I may have used nbt tags in my contraptions that are no longer supported, however just turning off the clocks powering the contraptions did not fix the issue.
2) the command blocks themselves have gotten corrupted. At some point in my play on the snapshots I ended up corrupting the chunk they are loaded in, causing them to be deleted. To repair this, I used MCedit to copy and paste just that chunk back into the world. This may have introduced some corruption due to mc edit being in development for snapshots.
3) Command blocks are just currently buggy in some way.
To do some further testing I plan on rebuilding my contraption by hand. I'll be keeping an eye on the console as I do to see if/when the errors return. If they do return, I'll have to suspect that 3 is the issue. 1 seems unlikely since the errors persisted even when the command blocks were not actually being used. I'll definitely double check all of my NBT tags just in case though.
I'll check back in when I get the chance to do this test.
Update: Well the issue came back even before I had a chance to rebuild the command block contraptions... So the issue is somewhere else entirely.
Update 2: I did a "/kill @e" and that cleared the error. I then restored from backup and tried targeting my kill command more. I first hit my villager breeder that had about 40 villagers in it, thinking maybe one was corrupt. That didn't clear it. Then I killed the villagers in my iron farm which acts as the fake village for the breeder... and it stopped instantly.
I then restored again and instead of killing the villagers, I broke all of the doors in the area. Fixed again.
The doors are now all back in place and the iron farm/villager breeder are working again, so the village has been restored and the errors are gone.
So it would appear that something was wrong with the village itself.
Just so, I'll keep an eye on this for a while and report back if the errors return.
Update 3: The errors came back shortly after re-creating the village.
So I deleted all of the doors again, then put only one back. I got the same error message repeating.
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
7:28:59 PM CONSOLE: : vm@273c81de
With 2 doors in the village
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
7:30:49 PM CONSOLE: : vm@273c81de
7:30:49 PM CONSOLE: : vm@4ef10fac
3 doors and the error went away again...
4 doors and the error stayed away...
I've now added all of my doors back and am waiting to see what happens. So far 5 minutes have passed and the errors are still gone.
Update 4: Yep, came back. Seems to be one error per door in the village. Starts after the first Iron Golem spawns. I get one Iron Golem, and then no more.
7:55:30 PM CONSOLE: : vm@10c745c4
7:55:30 PM CONSOLE: : vm@47b6240e
7:55:30 PM CONSOLE: : vm@6375fc26
7:55:30 PM CONSOLE: : vm@10ee4711
7:55:30 PM CONSOLE: : vm@26378a6b
7:55:30 PM CONSOLE: : vm@56538a3c
7:55:30 PM CONSOLE: : vm@1fd3578d
7:55:30 PM CONSOLE: : vm@531b60dc
7:55:30 PM CONSOLE: : vm@4ce5f695
7:55:30 PM CONSOLE: : vm@10c745c4
7:55:30 PM CONSOLE: : vm@47b6240e
7:55:30 PM CONSOLE: : vm@6375fc26
7:55:30 PM CONSOLE: : vm@10ee4711
7:55:30 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@6375fc26
7:55:31 PM CONSOLE: : vm@10ee4711
7:55:31 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@56538a3c
7:55:31 PM CONSOLE: : vm@1fd3578d
7:55:31 PM CONSOLE: : vm@531b60dc
7:55:31 PM CONSOLE: : vm@4ce5f695
7:55:31 PM CONSOLE: : vm@10c745c4
7:55:31 PM CONSOLE: : vm@47b6240e
7:55:31 PM CONSOLE: : vm@6375fc26
7:55:31 PM CONSOLE: : vm@10ee4711
7:55:31 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@56538a3c
7:55:31 PM CONSOLE: : vm@1fd3578d
7:55:31 PM CONSOLE: : vm@531b60dc
7:55:31 PM CONSOLE: : vm@4ce5f695
7:55:31 PM CONSOLE: : vm@10c745c4
7:55:31 PM CONSOLE: : vm@47b6240e
7:55:31 PM CONSOLE: : vm@6375fc26
7:55:31 PM CONSOLE: : vm@10ee4711
7:55:31 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@56538a3c
7:55:31 PM CONSOLE: : vm@1fd3578d
7:55:31 PM CONSOLE: : vm@531b60dc
7:55:31 PM CONSOLE: : vm@4ce5f695
7:55:31 PM CONSOLE: : vm@10c745c4
7:55:31 PM CONSOLE: : vm@47b6240e
7:55:31 PM CONSOLE: : vm@6375fc26
7:55:31 PM CONSOLE: : vm@10ee4711
7:55:31 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@56538a3c
7:55:31 PM CONSOLE: : vm@1fd3578d
7:55:31 PM CONSOLE: : vm@531b60dc
7:55:31 PM CONSOLE: : vm@4ce5f695
7:55:31 PM CONSOLE: : vm@10c745c4
7:55:31 PM CONSOLE: : vm@47b6240e
7:55:31 PM CONSOLE: : vm@6375fc26
7:55:31 PM CONSOLE: : vm@10ee4711
7:55:31 PM CONSOLE: : vm@26378a6b
7:55:31 PM CONSOLE: : vm@56538a3c
7:55:31 PM CONSOLE: : vm@1fd3578d
7:55:31 PM CONSOLE: : vm@531b60dc
7:55:32 PM CONSOLE: : vm@4ce5f695
7:55:32 PM CONSOLE: : vm@10c745c4
7:55:32 PM CONSOLE: : vm@47b6240e
7:55:32 PM CONSOLE: : vm@6375fc26
7:55:32 PM CONSOLE: : vm@10ee4711
7:55:32 PM CONSOLE: : vm@26378a6b
7:55:32 PM CONSOLE: : vm@56538a3c
7:55:32 PM CONSOLE: : vm@1fd3578d
7:55:32 PM CONSOLE: : vm@531b60dc
7:55:32 PM CONSOLE: : vm@4ce5f695
7:55:32 PM CONSOLE: : vm@10c745c4
7:55:32 PM CONSOLE: : vm@47b6240e
7:55:32 PM CONSOLE: : vm@6375fc26
7:55:32 PM CONSOLE: : vm@10ee4711
7:55:32 PM CONSOLE: : vm@26378a6b
7:55:32 PM CONSOLE: : vm@56538a3c
7:55:32 PM CONSOLE: : vm@1fd3578d
7:55:32 PM CONSOLE: : vm@531b60dc
7:55:32 PM CONSOLE: : vm@4ce5f695
7:55:32 PM CONSOLE: : vm@10c745c4
7:55:32 PM CONSOLE: : vm@47b6240e
7:55:32 PM CONSOLE: : vm@6375fc26
It would seem so from my limited testing. Also that the message changes depending on if the villager is inside or outside the house.