My node devices recently started crashing

I have three Bluesound devices: Node 2i, Pulse Mini, and Soundbar.  All are streaming a large library (75,000+) of flac files from a Synology NAS.  Everything is on gigabit ethernet (no wifi).  All have worked well for years with very little trouble until the past few weeks.  Suddenly, both the Node 2i and Pulse Mini now often stop during playback and reboot automatically.  I haven't used the Soundbar recently so I don't know if it its having the same issue or not.  Nothing on my network has changed.  It happens whether I use an iOS controller or a Mac controller.  It happens randomly when listening to an album but I also seem to be able to make it happen more frequently if I click the "next" arrow a few times to skip songs.  Whats going on?  I am a long time Bluesound user.  Please help.