Problem with file name containing an '_' with the structurer

At least the generation of :
  - changes_X.Y.html
  - changes_current.html
  - releaseNotes_X.Y.html
  - releaseNotes_current.html
(Where X.Y is a version ...)

gives the following error :
X [0] changes_current.html BROKEN: Erreur de ElemTemplateElement : dotdots

It is strange because the intermediate format or the body.xml is good - I have checked it with the forrest bar.
It seams that the pipelines are good. I don't know where it comes from...