Yes, I did extend the Kings River all the way to its source, going from "river" to "stream" to "intermittent stream" in the process.  I haven't noticed anyone else doing much work while I've been cleaning up the map in this area.

Some OSM consumers are a bit slower to get updates.  I've noticed Mapbox is very quick to get road updates but their waterway updates are more delayed, so you might see road changes from a month ago but no waterway changes more recent than several months.  Wikipedia Maps is really inconsistent with the map tiles, with some being fairly new but adjacent tiles being a year or more old; I don't think they have a good algorithm for regenerating their tiles.  But on the main OSM site of course everything should be current within minutes or hours at worst.

Basically my project now is to do a full TIGER road cleanup in NW Arkansas, and then also add streams as appropriate.  In Washington County, nearly all rivers and streams and many intermittent streams were already imported as "streams" so it was mostly just a matter of properly classifying them, but for the other counties the rivers and streams are largely missing entirely so I've been adding them.  My ultimate goal is to add any stream from the USGS topo maps that is visible on either the ADOP imagery or the USGS 3D elevation model; some I am skipping because there's really no evidence on either of the two photographic sources.  However, this is a big enough task that in some areas I've just focused on the more major streams while doing the TIGER cleanup.

I'm pretty much done with the TIGER cleanup portion in 6 NW AR counties (Benton, Washington, Carroll, Madison, Boone, and Newton), but as time permits I plan to do more.  I've not been quite as comprehensive with the streams yet, but the vast majority should be there now in those counties.