Export XML contains wrongly formatted control codes

(Was supposed to be XWiki v4, but maybe the same issue is there in 3)
Exported XML's contain (at least when using the WYSIWYG editor) XML control codes. Only the formatting is wrong, rendering the XML useless for import. When for instance code 0x28 is inserted, it's written as  while for a hex value it should be (
As work-around I extracted all files, did a replace in files using notepad++ (&# to &#x) and re-zipped the files. Then I could import.