All command blocks lose all nbt data on update to 18w20a

[17:14:50] [Server thread/ERROR]: Failed to load data for block entity minecraft:command_block
com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
       at com.google.gson.internal.Streams.parse(Streams.java:60) ~[minecraft_server.jar:?]
       at com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:65) ~[minecraft_server.jar:?]
       at wq.a(SourceFile:493) ~[minecraft_server.jar:?]
       at wq.a(SourceFile:518) ~[minecraft_server.jar:?]
       at ic$a.a(SourceFile:243) ~[minecraft_server.jar:?]
       at bam.b(SourceFile:69) ~[minecraft_server.jar:?]
       at bmj.b(SourceFile:45) ~[minecraft_server.jar:?]
       at bmf.c(SourceFile:78) [minecraft_server.jar:?]
       at bqb.a(SourceFile:496) [minecraft_server.jar:?]
       at bqb.a(SourceFile:101) [minecraft_server.jar:?]
       at si.g(SourceFile:94) [minecraft_server.jar:?]
       at si.b(SourceFile:118) [minecraft_server.jar:?]
       at si.a(SourceFile:160) [minecraft_server.jar:?]
       at net.minecraft.server.MinecraftServer.g_(SourceFile:384) [minecraft_server.jar:?]
       at net.minecraft.server.MinecraftServer.a(SourceFile:336) [minecraft_server.jar:?]
       at ru.d(SourceFile:248) [minecraft_server.jar:?]
       at net.minecraft.server.MinecraftServer.run(SourceFile:497) [minecraft_server.jar:?]
       at java.lang.Thread.run(Unknown Source) [?:1.8.0_161]
Caused by: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
       at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1559) ~[minecraft_server.jar:?]
       at com.google.gson.stream.JsonReader.checkLenient(JsonReader.java:1401) ~[minecraft_server.jar:?]
       at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:593) ~[minecraft_server.jar:?]
       at com.google.gson.stream.JsonReader.peek(JsonReader.java:425) ~[minecraft_server.jar:?]
       at com.google.gson.internal.Streams.parse(Streams.java:46) ~[minecraft_server.jar:?]
       ... 17 more