Jetty 9.3 and 9.4 fail to start as soon as I apply the keycloak adapter to my jetty_base

Tomas@DESIGN MINGW64 /D/devtools/jetty-distribution-9.3.29.v20201019/jetty_base
java -jar ../start.jar --create-startd --add-to-start=keycloak INFO: server initialised (transitively) in {jetty.base}\start.ini
INFO: keycloak initialised in ${jetty.base}\start.ini
INFO: Base directory was modified

Tomas@DESIGN MINGW64 /D/devtools/jetty-distribution-9.3.29.v20201019/jetty_base
$ java -jar …/start.jar
java.nio.file.InvalidPathException: Illegal char <:> at index 6: ~ http:\www.apache.org\licenses
at sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182)
at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153)
at sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77)
at sun.nio.fs.WindowsPath.parse(WindowsPath.java:94)
at sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:255)
at java.io.File.toPath(File.java:2234)
at org.eclipse.jetty.start.PathMatchers.asPath(PathMatchers.java:73)
at org.eclipse.jetty.start.PathMatchers.getSearchRoot(PathMatchers.java:191)
at org.eclipse.jetty.start.PathMatchers.isAbsolute(PathMatchers.java:221)
at org.eclipse.jetty.start.BaseHome.getPaths(BaseHome.java:356)
at org.eclipse.jetty.start.StartArgs.expandModules(StartArgs.java:485)
at org.eclipse.jetty.start.Main.processCommandLine(Main.java:333)
at org.eclipse.jetty.start.Main.main(Main.java:75)

Usage: java -jar start.jar [options] [properties] [configs]
java -jar start.jar --help # for more information