Set-User without -Email property is removing email address from profile

[sandyfoley]

Hello -

The email address field value is getting deleted from the user profile when using Set-User.

Note that in the code below, the -Email property is not set in Set-User, which is not a required property .
'foo' does exist as a custom property on the profile.

`$users = Get-User -Filter $userFilter
foreach ( $user in $users )
{
$profile = $user.Profile
$identity = $profile.Username

Set-User -Identity $identity -CustomProperties @{ "foo" = "bar" }
}`

This occurs in SPE 5.1.
Thanks (again) for this awesome module for Sitecore.