Function New-ValidationDynamicParam
{
    [CmdletBinding()]
    [OutputType('System.Management.Automation.RuntimeDefinedParameter')]
    param (
        [Parameter(Mandatory)]
        [ValidateNotNullOrEmpty()]
        [string]$Name,
        [ValidateNotNullOrEmpty()]
        [Parameter(Mandatory)]
        [array]$ValidateSetOptions,
        [Parameter()]
        [switch]$Mandatory = $false,
        [Parameter()]
        [string]$ParameterSetName = '__AllParameterSets',
        [Parameter()]
        [switch]$ValueFromPipeline = $false,
        [Parameter()]
        [switch]$ValueFromPipelineByPropertyName = $false
    )
    $AttribColl = New-Object System.Collections.ObjectModel.Collection[System.Attribute]
    $ParamAttrib = New-Object System.Management.Automation.ParameterAttribute
    $ParamAttrib.Mandatory = $Mandatory.IsPresent
    $ParamAttrib.ParameterSetName = $ParameterSetName
    $ParamAttrib.ValueFromPipeline = $ValueFromPipeline.IsPresent
    $ParamAttrib.ValueFromPipelineByPropertyName = $ValueFromPipelineByPropertyName.IsPresent
    $AttribColl.Add($ParamAttrib)
    $AttribColl.Add((New-Object System.Management.Automation.ValidateSetAttribute($Param.ValidateSetOptions)))
    $RuntimeParam = New-Object System.Management.Automation.RuntimeDefinedParameter($Param.Name, [string], $AttribColl)
    Return $RuntimeParam
}

Function DP-Bug
{
    [CmdletBinding()]
    Param
    (
        [ValidateSet("NoSpace","Yes Space")]
        [string]$Param1
    )

    DynamicParam
    {
        $ParamOptions = @(
            @{
                'Name' = 'Param2';
                'Mandatory' = $True;
                'ValidateSetOptions' = @(
                    'Option 1',
                    'Option 2'
                )
            })
        $RuntimeParamDic = New-Object System.Management.Automation.RuntimeDefinedParameterDictionary
        foreach ($Param in $ParamOptions)
        {
            $RuntimeParam = New-ValidationDynamicParam @Param
            $RuntimeParamDic.Add($Param.Name, $RuntimeParam)
        }
        Return $RuntimeParamDic
    }
    begin
    {
        Write-Output "OK"
    }
}

DP-Bug -Param1 NoSpace -<tab>
DP-Bug -Param1 'Yes Space' -<tab>

Name                           Value
----                           -----
PSVersion                      5.0.10586.117
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.10586.117
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1