Occasional failure to connect when using multiple Subscribe + Execute invocations

[palcs]

High-Level Problem

A .NET 8 service application that subscribes to messages from PubNub and, upon upgrade/restart, will occasionally get into a state where it cannot connect to PubNub until the application is restarted again.

Notes

• The .NET application is .NET 8 (as time of this writing, v8.0.200).
• Using NuGet PubnubPCL v6.19.7 (latest as of April 16, 2024).
• Using ReconnectionPolicy repeatedly fails to connect to PubNub.
• The current nature of the .NET application is to perform multiple Subscribe() + Execute() invocations when an entity from a separate system is "discovered" (e.g. Discover Entity A then perform Subscribe().Channels("entity-A-notification-type1").Execute()).
• My personal gut feeling is a thread synchronization issue, possibly somewhere around ClientNetworkStatus.RefHttpClient = httpClientNetworkStatus.
• When I add a project reference to PubnubApiPCL.csproj, I caught this state where, somehow, there is a header with a null key (.NET thread safety issue with HTTP headers?).
  

Reproduction

I have attached a simple application (from a Windows system). You will need to populate SubscribeKey, AuthKey, and channels with real values. Afterwards, you can run the script run.bat which should build and then re-start the application until the problem eventually reproduces; the output will indicate a failure to connect (ERROR Internet connection problem. Retrying connection Cat=PNNetworkIssuesCategory). I usually have it reproduce within about 30 seconds.
ReproductionApp.zip

The application is fairly straightforward: create the Pubnub instance, perform Subscribe().Channels(...).Execute() multiple times, then wait about 2 seconds for connection messages before exiting.