The weaponsmith building has an issue where bats spawn inside the hollow roofs; up to 16 bats can spawn in the roof at a time, which is an unnecessary annoyance for players.
you can experience it by finding a village with a weaponsmith in a superflat world. (Low block count could possibly have something to do with it, so a classic superflat world would probably be best.)
Thank you for your report!
We're actually already tracking this issue at MC-140448, so we will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
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