17w48a crash log upon loading structure

18:57:13	bmm	Client thread	fatal	Reported exception thrown!
f: Rendering Block Entity
	at cbn.a(SourceFile:141)
	at cbn.a(SourceFile:122)
	at bzo.a(SourceFile:673)
	at bzi.b(SourceFile:1185)
	at bzi.a(SourceFile:1093)
	at bzi.a(SourceFile:951)
	at bmm.b(SourceFile:820)
	at bmm.a(SourceFile:381)
	at net.minecraft.client.main.Main.main(SourceFile:134)
Caused by: java.lang.IllegalArgumentException: Cannot get property bbc{name=facing, clazz=class dz, values=[north, east, south, west]} as it does not exist in baq{block=minecraft:air, properties=[]}
	at baq$a.c(SourceFile:174)
	at cbu.a(SourceFile:37)
	at cbu.a(SourceFile:18)
	at cbn.a(SourceFile:134)
	... 8 more