PowerShell "break" keeps changing the rules

Question

This line of code has - without editing it - changed it's behavior over the last several days - several times:

try {
    $testfile = "c:\users\***RedactedForSecurity***\desktop\psfcatalog\copy_conversions_weekly_report.csv"
    write-log((Get-Date -Format o) + "     get-sqlhelper")
    $sqlhelper = get-sqlhelper -serverinstance '***RedactedForSecurity***' -database '***RedactedForSecurity***' -username '***RedactedForSecurity***' -password '***RedactedForSecurity***'

    Function Create-TableString{ 
        Param(
            [Parameter(Mandatory=$true)]
            [string]$tableName,
            [Parameter(Mandatory=$true)]
            [string]$Fields
        )
        [string]$SQL = "CREATE TABLE " + $tableName + '(' + $Fields + ')'
        Write-Host $SQL
        return $SQL
    }

    write-log((Get-Date -Format o) + "     finding first line of CSV data in file")
    gc $testfile | % {
        if ($_ -match "report fields") {
            $line = $_.ReadCount
            break
        }
    }

    [string]$fieldNamesSQL = gc $testfile |
        select -Skip $line -First 10 |
        ConvertFrom-Csv |
        Out-DataTable |
        % {$fieldNamesSQL += $Col.ColumnName + " VARCAR(255)  NULL, "} -End {$fieldNamesSQL.TrimEnd(',', ' ')}

    Write-Host $fieldNamesSQL
    Write-Host $csvHeaders
} catch {
    $msg = command 2>&1
    Write-Host $_.exception.message
    Write-Host $_.exception.itemname
    Write-Host $_.exception.message
    Write-Host $msg
}

Alright here's the thing - notice the portion of the script:

gc $testfile | % {
    if ($_ -match "report fields") {
        $line = $_.ReadCount
        break
    }
}

That portion worked fine for about a day and then break started to stop execution of the entire script instead of just beak the loop. How can it work for a day and then change? Anyway, I came up with a solution where I would wrap the whole piece with {} and then recursivly execute it in my next call:

{gc $testfile | % {
    if ($_ -match "report fields") {
        $line = $_.ReadCount
        break
    }
}}

[string]$fieldNamesSQL = gc $testfile |
    select -Skip $line -First 10 |
    ConvertFrom-Csv |
    Out-DataTable |
    % {$fieldNamesSQL += $Col.ColumnName + " VARCAR(255)  NULL, "} -End {$fieldNamesSQL.TrimEnd(',', ' ')}

With this setup when $line is called, it evaluates the previous line and script execution continues seamlessly.

A day later...

Now the same script is throwing an error:

Cannot validate argument on parameter 'Skip'. The argument is null, empty, or an element of the argument collection contains a null value. Supply a collection that does not contain any null values and then try the command again.

What is happening?

Edit

This is not a duplicate. I'm aware of the foreach alias problem. The question is why the PowerShell runtime changes its evaluation between executions. Ie: I didn't change the script but the execution changed. Why would PowerShell evaluate foreach to an operator on one day and evaluate it to ForEach-Object on another day?

Things I've found:

It seems that PowerShell persists certain values between executions. For instance if I set a string to value1 and run the script. Then I set it to another value2 and run the script, but the value remains value1 when I Write-Host. I have to restart the shell and sometimes the machine to get it to evaluate correctly. It seems random so far as to when this happens - which probably just means I don't understand it.

My best guess so far is that when PowerShell interprets foreach it does so recursively so a function further down the script could cause it to evaluate differently from call to call.