Nested comments in XML?
No, the string -- is not permitted to appear within comments in XML. So the fact you have -- show up inside another comment is going to cause failures.
And trying to post that answer also broke the text entry parsing ;)
For further proof, check the W3C specification:
http://www.w3.org/TR/2008/REC-xml-20081126/#sec-comments
The phrase
For compatibility, the string " -- " (double-hyphen) MUST NOT occur within comments.]
appears in the first paragraph of the section on XML comments.
As it is said in How do I comment out a block of tags in XML?, you can try to wrap your code with a non-existing processing-instruction, e.g.:
<?ignore<component> <!-- Result observation template --> <!-- <id root="2.16.840.1.113883.19.5.10" extension="103220"/> </component> ?>