I've encountered issues with projections in .geojson files created by rgdal, but I never thought it would destroy my data, until I tried this (reproducible example):
downloader::download("http://census.edina.ac.uk/ukborders/easy_download/prebuilt/shape/England_lad_2011_gen_clipped.tar.gz", destfile = "cuas.zip")untar("cuas.zip")cuas_shp
downloader::download("http://census.edina.ac.uk/ukborders/easy_download/prebuilt/shape/England_lad_2011_gen_clipped.tar.gz", destfile = "cuas.zip")untar("cuas.zip")cuas_shp