Absolutely - this is why I don’t like to jump to conclusions, and like to look at the logs as they only tell the facts (not all of them of course, but what they do say is factual) 
How many times have you tried this? I’m not, not believing you, but something I see a lot is “if I do X, it works” - and often it’s nothing to do with “X” - it just happened to work that once so the conclusion is drawn.
On this problem, from looking at the logs from your failed inclusion, there’s nothing in there that’s showing any external problem. Maybe there is something going on that’s not in the logs, but I think it’s unlikely that these external influences only appear during secure inclusion. Honestly, I’d be much happier if there was a bug in the binding as we can fix that - if we’re saying “it’s ghosts and goblins at work” then, well, that’s just not engineering :).
Let’s sit on this for now. If you have the opportunity to try a fresh install with a device, then it might be interesting. Otherwise, hopefully I’ll get this BE469 in the coming days and maybe the issues there will shed some light on the problem. Of course, if there really is an issue with the number of devices, then the BE469 isn’t going to help since it’s (nearly) the only US device I’ll have so I won’t be able to build a network 