NPE when compiling simple-fixed (classloader)

[sake92]

PS C:\cbt\test\simple-fixed> cbt compile
INFO: Could not find files for the given pattern(s).
Compiling to C:\cbt\test\simple-fixed\build\target\scala-2.11\classes
[info] Compile success at Jan 12, 2018 11:57:08 PM [1.505s]
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Compiling to C:\cbt\cache\git\github.com\cvogt\cbt\e8673866b79f7473391dcee26243eee80d5d3cb6\nailgun_launcher\target\scala-2.11\classes
[info] Compile success at Jan 12, 2018 11:57:10 PM [0.196s]
[info] Compile success at Jan 12, 2018 11:57:11 PM [1.419s]
Exception in thread "main" java.lang.NullPointerException
        at cbt.MultiClassLoader2.findClass(MultiClassLoader2.java:18)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:411)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at cbt.CbtURLClassLoader.loadClass(CbtURLClassLoader.java:20)
        at cbt.NailgunLauncher.getBuild(NailgunLauncher.java:41)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at cbt.DirectoryDependency$$anonfun$loadCustomBuildWithDifferentCbtVersion$1$2.apply(DirectoryDependency.scala:69)
        at cbt.DirectoryDependency$$anonfun$loadCustomBuildWithDifferentCbtVersion$1$2.apply(DirectoryDependency.scala:51)
        at scala.Option.flatMap(Option.scala:171)
        at cbt.DirectoryDependency$.loadCustomBuildWithDifferentCbtVersion$1(DirectoryDependency.scala:51)
        at cbt.DirectoryDependency$.cbt$DirectoryDependency$$loadBuild$1(DirectoryDependency.scala:38)
        at cbt.DirectoryDependency$$anonfun$apply$4.apply(DirectoryDependency.scala:119)
        at cbt.DirectoryDependency$$anonfun$apply$4.apply(DirectoryDependency.scala:118)
        at cbt.LazyDependency.dependency$lzycompute(LazyDependency.scala:3)
        at cbt.LazyDependency.dependency(LazyDependency.scala:3)
        at cbt.LazyDependency.show(LazyDependency.scala:9)
        at cbt.LazyDependency.moduleKey$lzycompute(LazyDependency.scala:8)
        at cbt.LazyDependency.moduleKey(LazyDependency.scala:8)
        at cbt.Dependencies$$anonfun$moduleKey$1.apply(resolver.scala:171)
        at cbt.Dependencies$$anonfun$moduleKey$1.apply(resolver.scala:171)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
        at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
        at scala.collection.Iterator$class.foreach(Iterator.scala:893)
        at scala.collection.AbstractIterator.foreach(Iterator.scala:1336)
        at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
        at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
        at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
        at scala.collection.AbstractTraversable.map(Traversable.scala:104)
        at cbt.Dependencies.moduleKey$lzycompute(resolver.scala:171)
        at cbt.Dependencies.moduleKey(resolver.scala:171)
        at cbt.DependencyImplementation$class.taskCache(resolver.scala:20)
        at cbt.Dependencies.taskCache$lzycompute(resolver.scala:169)
        at cbt.Dependencies.taskCache(resolver.scala:169)
        at cbt.DependencyImplementation$class.dependencyClasspath(resolver.scala:126)
        at cbt.Dependencies.dependencyClasspath(resolver.scala:169)
        at cbt.DependencyImplementation$class.classpath(resolver.scala:124)
        at cbt.Dependencies.classpath(resolver.scala:169)
        at cbt.Stage1Lib.compile(Stage1Lib.scala:148)
        at cbt.BaseBuild$$anonfun$compile$1.apply(BasicBuild.scala:168)
        at cbt.BaseBuild$$anonfun$compile$1.apply(BasicBuild.scala:168)

OS: Windows
Nailgun used: no