Just adding <# #> allows Get-Help to see the parameter attribute help. Removing <# #> breaks Help even if the parameter attributes are present.

Fails.ps1

function Test-WildCardsWorks
{
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory=$true,
                   Position=0,
                   ParameterSetName="Path",
                   ValueFromPipeline=$true,
                   ValueFromPipelineByPropertyName=$true,
                   HelpMessage="Path to one or more locations.")]
        [SupportsWildcards()]
        [PSDefaultValue(Help='*')]
        [ValidateNotNullOrEmpty()]
        [string[]]$Path = '*',

        [Parameter(Mandatory=$false, Position=1)]
        [SupportsWildCards()]
        [PSDefaultValue(Help='*')]
        [String[]]$Name ="*"
    )
    
    Begin
    {
        
    }
    
    Process
    {
        $path | Where-Object { $_.Fullname -like 'test' }
    }
    
    End
    {
        
    }
}

FailsOutput.ps1

NAME
    Test-WildCardsFails
    
SYNTAX
    Test-WildCardsFails [-Path] <string[]> [[-Name] <string[]>]  [<CommonParameters>]
    
    
PARAMETERS
    -Name <string[]>
        
        Required?                    false
        Position?                    1
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        
    -Path <string[]>
        Path to one or more locations.
        
        Required?                    true
        Position?                    0
        Accept pipeline input?       true (ByValue, ByPropertyName)
        Parameter set name           Path
        Aliases                      None
        Dynamic?                     false
        
    <CommonParameters>
        This cmdlet supports the common parameters: Verbose, Debug,
        ErrorAction, ErrorVariable, WarningAction, WarningVariable,
        OutBuffer, PipelineVariable, and OutVariable. For more information, see 
        about_CommonParameters (http://go.microsoft.com/fwlink/?LinkID=113216). 
    
    
INPUTS
    System.String[]
    
    
OUTPUTS
    System.Object
    
ALIASES
    None
    

REMARKS
    None

Works.ps1

function Test-WildCardsWorks
{
<#
#>
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory=$true,
                   Position=0,
                   ParameterSetName="Path",
                   ValueFromPipeline=$true,
                   ValueFromPipelineByPropertyName=$true,
                   HelpMessage="Path to one or more locations.")]
        [SupportsWildcards()]
        [PSDefaultValue(Help='*')]
        [ValidateNotNullOrEmpty()]
        [string[]]$Path = '*',

        [Parameter(Mandatory=$false, Position=1)]
        [SupportsWildCards()]
        [PSDefaultValue(Help='*')]
        [String[]]$Name ="*"
    )
    
    Begin
    {
        
    }
    
    Process
    {
        $path | Where-Object { $_.Fullname -like 'test' }
    }
    
    End
    {
        
    }
}

WorksOutput.ps1

NAME
    Test-WildCardsWorks
    
SYNTAX
    Test-WildCardsWorks [-Path] <string[]> [[-Name] <string[]>]  [<CommonParameters>]
    
    
PARAMETERS
    -Name <string[]>
        
        Required?                    false
        Position?                    1
        Accept pipeline input?       false
        Parameter set name           (All)
        Aliases                      None
        Dynamic?                     false
        
    -Path <string[]>
        Path to one or more locations.
        
        Required?                    true
        Position?                    0
        Accept pipeline input?       true (ByValue, ByPropertyName)
        Parameter set name           Path
        Aliases                      None
        Dynamic?                     false
        
    <CommonParameters>
        This cmdlet supports the common parameters: Verbose, Debug,
        ErrorAction, ErrorVariable, WarningAction, WarningVariable,
        OutBuffer, PipelineVariable, and OutVariable. For more information, see 
        about_CommonParameters (http://go.microsoft.com/fwlink/?LinkID=113216). 
    
    
INPUTS
    System.String[]
    
    
OUTPUTS
    System.Object
    
ALIASES
    None
    

REMARKS
    None