Custom JRE cannot find non-ASCII named module inside

Custom JRE generated by jlink cannot find non-ASCII named modules included inside the JRE.

Recreate steps:
$ javac -d mod1 あ.java module-info.java
$ mkdir jars
$ jar --create -f jars/あ_module.jar --main-class test.isel.あ.あ -C mod1 .
$ jlink --module-path jars --add-modules あ_module --output myjava
$ myjava/bin/java -m あ_module
Error: Could not find or load main class test.isel.あ.あ in module あ_module

Expected result:
$ myjava/bin/java -m あ_module
calling:main

----module-info.java
module あ_module {
    exports test.isel.あ;
}
----
----あ.java
package test.isel.あ;

public class あ{
    public static void main(String[] args) {
        System.out.println("calling:main");
    }
}
----