I am running the 1903 update on multiple computers, and I have had zero problems accessing either my new Netgear ReadyNAS or a very old Seagate NAS. Not only does every W10 computer and every application access the audio, video, and data files just fine, but my Android phones AND my Samsung TV have no problems playing the music or videos stored there either.
In addition, just in the last week I copied around 6TB of files to the ReadyNAS without problems. I have not, however, done any similar mass copies back from the NAS.