When you craft certain recipes in the recipe book, it can cause the game to crash and this ends up in the log:

[19:32:59] [Client thread/FATAL]: Reported exception thrown![19:32:59] [Client thread/FATAL]: Reported exception thrown!h: mouseClicked event handler at cmk.a(SourceFile:434) ~[1.13-pre2.jar:?] at civ.a(SourceFile:67) ~[1.13-pre2.jar:?] at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:23) ~[lwjgl-glfw-3.1.2.jar:?] at org.lwjgl.system.JNI.invokeV(Native Method) ~[lwjgl-3.1.2.jar:?] at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:2520) ~[lwjgl-glfw-3.1.2.jar:?] at cjd.a(SourceFile:291) ~[1.13-pre2.jar:?] at cit.c(SourceFile:841) ~[1.13-pre2.jar:?] at cit.a(SourceFile:379) [1.13-pre2.jar:?] at net.minecraft.client.main.Main.main(SourceFile:144) [1.13-pre2.jar:?]Caused by: java.lang.NullPointerException at com$a.a(SourceFile:237) ~[1.13-pre2.jar:?] at oj.a(SourceFile:50) ~[1.13-pre2.jar:?] at com$a.a(SourceFile:231) ~[1.13-pre2.jar:?] at com$a.<init>(SourceFile:227) ~[1.13-pre2.jar:?] at com.a(SourceFile:97) ~[1.13-pre2.jar:?] at cop.a(SourceFile:175) ~[1.13-pre2.jar:?] at coo.mouseClicked(SourceFile:315) ~[1.13-pre2.jar:?] at cnm.mouseClicked(SourceFile:112) ~[1.13-pre2.jar:?] at civ.b(SourceFile:67) ~[1.13-pre2.jar:?] at cmk.a(SourceFile:429) ~[1.13-pre2.jar:?] ... 8 more

This seems to occur with beds and boats (at least on multiplayer) as far as I know.