Odd PowerShell behavior and Add-Member - powershell

Question

Can someone help me understand why the $_ works differently for the Add-Member function than it seems to for other PowerShell functions? There must be some nuance that I am missing here.
Using the sample CSV file below, the first 3 examples work fine. The fourth, which seems pretty straightforward, does not. The error Powershell returns is:
The variable '$_' cannot be retrieved because it has not been set.
Is this "normal" or have I miscoded something?
Thanks in advance.
Test.csv
Column1,Column2, Column3
Rock,1,abc
Paper,2,efg
Scissors,3,hij
$obj = Import-CSV "C:\test.csv"
(1) $obj | Add-Member -MemberType NoteProperty -Name IdNumber -value "ROCK" -PassThru| Format-Table
(2) $obj | ForEach-Object { $_ | Add-Member -MemberType NoteProperty -Name IdNumber -value $_.Column1 ; $_} | Format-Table
(3) $obj | ForEach-Object { Add-Member -InputObject $_ -MemberType NoteProperty -Name IdNumber -value $_.Column1 ; $_ } | Format-Table
(4) $obj | Add-Member -MemberType NoteProperty -Name IdNumber -value $_.Column1 -PassThru| Format-Table

Answer 1

When you do this:
$obj | Add-Member -MemberType NoteProperty -Name IdNumber -value $_.Column1 -PassThru
You are accessing $_ outside of a pipeline bound context e.g. inside a foreach-object expression or within a scriptblock value specified for a pipeline bound parameter. The Value parameter is not pipeline bound. If it were you would be able to do this:
$obj | Add-Member -MemberType NoteProperty -Name IdNumber -value {$_.Column1} -PassThru
As it stands, the easiest way to do what you want is:
$obj | ForEach-Object { Add-Member -Inp $_ NoteProperty -Name IdNumber -Value $_.Column1 -PassThru } | Format-Table