Powershell $Error object not immediately populating inside PSM1 module

I'm encountering a peculiar issue with Powershell. I'm catching an Exception in a catch block, but the global $Error object is not being populated.

A trivial example, where this would behave as expected is this:

function Bar
{
  Foo
}

function Foo
{
  try
  {
    $Error.Clear()
    throw "Error!"
  }
  catch
  {
    "Caught an error - current error count $($Error.Count)"  
  } 
  finally
  {
    "Cleaning up - current error count $($Error.Count)"  
  }
}

Output is as you would expect if you call Bar

Caught an error - current error count 1
Cleaning up - current error count 1

The code I'm having trouble with is nearly identical, except that it loads Foo from a module. Not sure if this is a bug, or simply something I don't understand (will have to check my Powershell in Action book!)

If I save Foo off to a module - Foo.psm1

function Foo
{
  try
  {
    $Error.Clear()
    throw "Error!"
  }
  catch
  {
    "Caught an error - current error count $($Error.Count)"  
  } 
  finally
  {
    "Cleaning up - current error count $($Error.Count)"  
  }
}

Export-ModuleMember -Function Foo

Then I perform the following

Import-Module .\Foo.psm1
$Error.Clear()
"Current error count $($Error.Count)"
Foo
"Current error count $($Error.Count)"

I end up with

Current error count 0
Caught an error - current error count 0
Cleaning up - current error count 0
Current error count 1

Notice that Foo no longer sees any changes made to $Error. So the module-ification of the code is changing error propagation behavior. Can anyone chime in with the reasoning behind this?

I should note that I can get at the specific caught exception via the automatic variable $_, but I'm looking to get a hold of the entire collection at this point in the call stack.