Don't worry, it is only improved. Keep in mind that BLM (like USGS NHD, etc.) is just a set of points digitized (often in the 1970s) from paper maps, with all sorts of artifacts, inaccuracies and inefficiencies.  These come into OSM often minimally edited, resulting in redundant ways, overnoding, and innacuracies preserved sometimes from decades ago.  When cleaning these up, great care is taken to follow the actual bounds, where is it often easy to see where the original dataset's shortcomings, e.g. when a boundary should follow a river but was made from inaccurate river data long ago.