I’ve had pseudo-static IPs even when the problem occured (well, DHCP server assigning static ones based on mac address). Though the 6 hour DHCP timeout could be an explanation why it took longer than 2 hours here.
Happened to me on wireless only, not wired.
But ok, the last point sounds like the server having problems, that’s right. Though that you couldn’t connect to standard iTunes either (topic on Roku forum) seems to hint that the problem is a bit more general, since in SB-to-iTunes, Firefly would not be involved. Maybe some confusing broken multicasting packets from the SB?