naturalismus

Also affects 15w50a

@@unknown: So you're saying it is fixed in 15w42a although I have this bug in 15w42a since our world wasn't created in 15w42a? That's a funny definition of fixed.

@@unknown: I didn't test fresh worlds and have no interest in doing it, but it definitely affects old worlds in 15w42a. The affected world can be downloaded at http://api.wurstmineberg.de/v2/world/wurstmineberg/backup/latest.tar.gz
It occasionally happens while entering the end. It also happened to @unknown as described in the comments to MC-90605 while entering and exiting the nether.

Still effects SMP in 15w42a, occasionally.

(The named skeleton likely picked up an item, though. The only other nametagged mob that survived the update is a wither in our wood farm.)

@Anthony Martin: The crashes also happen when there is no villager around. As Fenhl said " Loading and unloading the Nether causes lag, and the watchdog kills the server when there's too much lag." Sometimes this happens when new chunks are generated, sometimes it happens when some Chunks are unloaded, sometimes it happens due to too many chickens, or players.

@Jason McDonald: On our server the problem seems to be worse with more people.

Tails: It's still a concern. I'm now certain that the issue is related to the mobfarm, since we can reproduce lags in a certain distance to the mobfarm if it is active, and the lags don't appear if the mobfarm is inactive. (However, sometimes freezes occur in random places for no reason. Sometimes in high terrain with a lot of waterfalls.)

Does the lag go away after a server restart?
The server was restarted 3 times since the problem first occured, so: no.
Does the lag appear after walking into a certain area?
At least for me, it didn't go away until I left a certain area and reappeared when I reentered. (I reentered again after we deactivated the mobfarm and nothing happened, but that may be a coincidence.)
Does the lag happen at the 12 chunk line (~192 blocks) from 0,0 (or spawn area)?
I'm not sure where that line is, may lag happened around x: -100, y: 14, z: 70, so within 12 chunks.
Is this hopper-clock within 12 chunks of spawn?
Yes.