Just ran into this issue

[MrChriZ]

Have to love Microsoft's usual lack of interest :(

[ducman]

Sorry, I'm guessing they (MS) have not fixed nor explained this in the latest version of Blazor (last I checked this issue was in .net5)?

They ignored/closed my post but I did run across another which was made by the author of Fluxor (which he ran into prior to us): dotnet/aspnetcore#23847

I'm guessing it is related to how HTTP clients are added or managed differently (again, not documented).

I ended up using local storage (since it is a singleton) as a hack.