IDEA fails to compile UTF16 file instrumented by Clover

Create a simple file with UTF16 encoding, e.g.:

public class Unicode16 {
    public static void main(String[] args) {
        char z = 'ż';
    }
}

(right click in source editor -> File Encoding -> UTF16)

Build with Clover fails with an error message like:

C:\Users\Marek\AppData\Local\Temp\javasyntax188072041083267764871javasyntax18\Unicode16.java
error: illegal character: '\u02d9'
error: illegal character: '\u0000'
error: illegal character: '\u0000'
...

Clover outputs instrumented file in the UTF8 format, so this might be a cause.

Note: the same UTF16 file compiles correctly in Eclipse.

It was reproduced just once. Probably due to UTF-8 - UTF-16 conversions, \u0000 characters were put in between and Clover rewrote it.