Sexpr's argument 'results=hide' ignored when rendering reference pages

[GeoBosh]

I am experimenting with pkgdown and am encountering some problems (in unusual situations) which look like bugs. I don't know enough details to make minimal examples, the notes below are with
https://github.com/GeoBosh/Rdpack

It seems that is Sexpr's argument 'results=hide' is ignored. An example:
https://github.com/GeoBosh/Rdpack/blob/master/man/Rdpack-package.Rd
starts with:

\name{Rdpack-package}
\alias{Rdpack-package}
\alias{Rdpack}
\docType{package}
\title{
  \Sexpr[stage=build,results=hide]{require(Rdpack)}
  \Sexpr[stage=build,results=hide]{pd <- packageDescription("Rdpack")}
  \Sexpr[stage=build,results=hide]{lb <- library(help="Rdpack", character.only=TRUE)}
  \Sexpr[stage=build]{pd$Title}
}

The result from require() (TRUE) and the whole package description end up in the 'Title' field of the rendered page.There are a number of warnings, as well, but all seem to stem from this.

[hadley]

pkgdown currently only has rudimentary \Sexpr{} support; we're implementing features as people ask for them.