I cannot speak to why these specific issues are occurring on these specific networks but in general it sounds like all the issues are network and/or non-Linn device issues.
There really is no such thing as network devices that never-ever have issues and Linn is not exempt from that. Yes I have had an issue or two over the 3-decades as a Linn Hi-Fi owner; and an issue or two over the past ten years as a DS / DSM owner. However overall I am beyond impressed with where Linn is today and their direction going forward.
I have a bit of a demanding home network environment, that has evolved and even again recently by replacing my entire network… during all of this Linn has never had network related issues like I am reading in this thread. And that is a big statement - especially when one is running (23) DS / DSM’s on a network, with all (23) running 24bit SongCast music without missing a beat (no pun intended - lol)
Everything I have stated has all been “Pre-Roon”… I have only this summer added Roon. I resisted it at first, tried it but didn’t really give it a fair shake but now that I have rolled it out, myself and everyone in the family now loves Roon.
I did have an issue initially trying to get the Roon Server and Linn working with the new network but after I made two changes on the router settings (IGMP snooping and IGMP Querier) everything immediately began working like a champ.
Regarding Air Play vs Linn Streaming via Roon: Air Play is reduced quality and I think it may be only 16bit whereas Linn Streaming is very high quality; I never choose Air Play.