The code

String pattern = "([0-9]{6})([0-9]{4})?(D|C|RD|RC)([A-Z])?([0-9\\,]{0,15})([A-Z]
[A-Z0-9]{3})(.{0,16})//(.{0,16})(\\n?(.{0,34}))?";
String text = "0405100510D99,99NABCKUNDENREF1\nKUNDENREF2";
RE re = new RE(pattern);
re.split(text);

causes an infinite loop within RE.matchNodes(). Tested with RegExp 1.2 and 1.3. 
Kind regards,

Andreas Berg.