The Samsung Galaxy Watch4 series received quite a few updates since the release, but the latest one seems to be the most mundane one. The changelog is pretty short - "improved system stability and reliability". That's it.
Perhaps the last update that installed a number of essential features cause some bugs and now the R870XXU1CUJ2 is here to fix them. Sadly, there's no additional info of what exactly does the new update address.
The update isn't available to all markets for now but will soon reach yours as well. Reportedly the US, among others, is the first one to get it.
Does the sleep tracking issue got resolved?