I was thinking that with a 3-way connection with HubConnect involving remote internet access maybe the latency between the remote servers would cause the issue. Something about the server having to ping all the hubs which could cause a delay or some such.
I have not heard of going through the HE Cloud for sharing data but I haven't had the need yet - wouldn't that add an extra hop instead of connecting directly? I do not really have experience with this so apologies..
The only reason I bring that up is if there is some sort of 3-way connection between the hubs with HubConnect maybe an extra slow client (like the US hub) can cause delays in the overall process which could muck up timing with Alexa stuff for the local processing in Ireland. Maybe the server is being impacted somehow is what I'm suggesting.
I use that configuration in my RV.. It frees me from worrying about managing a VPN connection. There is not a lot of devices in it so the traffic is minimal.
The communications are over http, so there's a bit of related protocol lag, but the real delay is mostly a direct correlation to the IP RTT latency between the two hubs and the cloud infrastructure in between.
Sending over http is asynchronous so the sending hub never sees any lag. Attribute updates are never acknowledged, so the recevier hub gets the update and moves on to the next message.