Unified Communications Architect, Pompey fan, burger eater, coffee drinker...
Wow, thanks for the response Ilya. I certainly never thought my little old blog post would get a reply from you (or anyone at Microsoft) on this.
Just a few comments on your comments:
Microsoft have said this is fixed in Version 1801 (Build 9001.2138). Details here: https://technet.microsoft.com/en-us/office/mt465751
Yup, it’s an annoying one. I’ll post here when I get confirmation it’s been fixed.