Doing some tests between myfaces core and orchestra I found that when h:link is rendered, the conversationContext param is rendered multiple times. It has two reasons:
1. It is called ExternalContext.encodeResourceURL from the rendered, but before it was called ViewHandler.getBookmarkableURL (on HtmlRendererUtils.getOutcomeTargetLinkHref). We need to remove the call to encodeResourceURL, because it is not necessary.
2. ExternalContext.encodeBookmarkableURL call _httpServletResponse.encodeURL and it should not. The reason is ViewHandler.getBookmarkableURL do this task calling ExternalContext.encodeActionURL.
I think this one has enough importance to be included in 2.0.0 release, so I'll regenerate all artifacts to include this one. Note this effect is only detected when myfaces core and orchestra are used together, because orchestra override HttpServletResponse.encodeURL to add his conversationContext param.