RedirectToAction in Core 3.1 MVC route values don't pass through if param has default

[Budsy]

This action won't load the parameter with a passed route value from a redirection because it has a default.

public IActionResult HelloWorld(string message="")
{
    ViewData["Message"] = message;  // If sent 'Howdy' from SendMsg() message will be empty 
    return View(); 
}
public IActionResult() SendMsg()
{
    return RedirectToAction("HelloWorld", new{ message="Howdy" });
}
/***********************************************/
// But this works ok if there is no default value on the param:
public IActionResult HelloWorld(string message)
{
    ViewData["Message"] = message;  // message will hold 'Howdy' now
    return View(); 
}

I never observed this before, so it might be a long-standing issues, normal behavior, or whatever.

[mkArtakMSFT]

Thanks for contacting us.
You can unblock yourself by not using the default value. We will move this to Backlog and see whether other customers also impacted by this. If yes, we'll prioritize this then.

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.