Crash when exploring with elytra . Ticking world caused by Cave spider

Was exploring in an old world updated to the 18w08b snapshot. When going to certain locations my game crashes and leaves me with the attached crash report.

Time: 24.02.18 21:50
Description: Exception ticking world

i: Non [a-z0-9/._-] character in path of location: minecraft:CaveSpider
at nx.<init>(SourceFile:36)
at nx.<init>(SourceFile:41)
at atj.g(SourceFile:42)
at atj.b(SourceFile:185)
at bfe.a(SourceFile:86)
at bfe.ac_(SourceFile:104)
at jp.<init>(SourceFile:53)
at sd.b(SourceFile:105)
at se.c(SourceFile:161)
at rx.k_(SourceFile:219)
at net.minecraft.server.MinecraftServer.w(SourceFile:694)
at net.minecraft.server.MinecraftServer.v(SourceFile:627)
at cxd.v(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:532)
at java.lang.Thread.run(Unknown Source)