The better work around for this issue should modifying MXParser.java file, especially the Line 378/379:
((codePoint >= 0x20) && (codePoint <= 0xD7FF)) ||
((codePoint >= 0xE000) && (codePoint <= 0xFFFD)) ||
Merge the two conditions into one condition:
((codePoint >= 0x20) && (codePoint <= 0xFFFD)) ||