Minor Description
A comment marker preceded by white spaces is not recognized as the start of a comment but Javadoc of java.util.Properties states that a comment can be preceded by white spaces: "A comment line has an ASCII '#' or '!' as its first non-white space character".
The bug can be fixed very simply: in the load() method just move up the following line of code
_extendedReader.skipCharacters(WHITESPACE);
so that it is the first line in the while loop.