Issue with Robocopy on Windows Server 2019

I've had a robocopy script running on Windows Server 2008 (Powershell version 4) with no issues for about 6 months now.

We've recently had to migrate off of this machine to initiate the same script off of a Windows Server 2019 (Powershell 5) machine. The exact same script no longer works, and i'm not quite sure what the issue is. The script is:

# Run BCP Bat file to get list of folders that have changed in the past 12 days and save them to 
\\xxxx\xxxx\xxx\xxx\xxx.bat

# Select the starting directory to pull the CSV from.  The assumption is  that  the DB file can #be sent to a dedicated directory that just has only the CSV files 
$Filerecentdir = "\\ZZZ\Z\ZZZ\ZZZZZ\ZZZZ\ZZZZZZ"
#

# Filtering for only CSV files
$Filter = "*.csv"
#

# This PS command will search for the file with  the latest timestamp on it.  Coupling this with #the filter above, we turn $Filerecent into a variable consisting of the most recent CSV
$Filerecent = Get-ChildItem -Path $Filerecentdir -Filter $Filter | Sort-Object LastAccessTime -Descending | Select-Object -First 1
#

# I concatenate $Filerecentdir with the $Filerecent variable to form the full path to the CSV
$FullPath = Join-Path -path $Filerecentdir -ChildPath $Filerecent
#

# $roboSource variable uses import-csv cmdlet to parameterize the one (headerless) column that #the DB file creates
$roboSource = Import-Csv -Header @("a") -Path $FullPath
#

# Arbitrary directory that i'm using to  store the logs.  We'll change this to something on the #file server so it can be viewable
$logPath = "\\AAAA\A\AAAA\AAAA\AAAA\AAAA\"

#creates a folder to seperate weekly logs based off the output of the bat script
$weeklylogfolder = $Filerecent -replace '_.csv'
New-Item -ItemType Directory -Force -Path "$($logPath)$($weeklylogfolder)"
#

# For each loop to iterate over every single row in the CSV
Foreach($script in $roboSource)
{
    # I used the two below variables to replace the two last trailing '\' in each entry
    $prefix = $script.a -replace '\{.+'
    $suffix = $script.a.Substring($prefix.Length) -replace '\\', '_' #keeping the {} in the file #name.
    #$suffix = $script.a.Substring($prefix.Length) -replace '[{}]' -replace '\\', '_'
    #

    #$logFileName = $prefix + $suffix
    $logFileName = $suffix
    #

    # Same switches that we used
    #$StandardSwitches = "/copy:DAT /s /dcopy:DAT /V /L" #no copy
    $StandardSwitches = "/copy:DAT /s /dcopy:DAT /V" #Copy
    #

    # Creates the log file in the same format that we used, so one log file per entry
    $log = "/log:`"$($logPath)$($weeklylogfolder)\$($logFileName).log`""
    #

    # Iterates through each row to create the source and destination
    $FileSource = "$($script.a)"
    $FileDestination = "$($script.a)"
    #

    # used this to surround the certain variables with double quotes, otherwise Robo fails
    $RoboArgs = '"I:\{0}" "Z:\{1}" {2} {3}' -f 
                $FileSource, $FileDestination, $StandardSwitches, $log

    #
    Robocopy $RoboArgs
}

I can't seem to pinpoint what would be causing the issue's I'm seeing. I've tried to run each of the commands within the script alone, and when I do, I am noticing that the $RoboArgs variable seems to cut off which then generates an incomplete $FileDestination

$RoboArgs with the above generates the exact same output as it does on server 2008/Powershell 4. However, it seems that powershell 5 processes this differently. Is there something I'm doing wrong or need to add in order to get this to process correctly?

EDIT:

Here's an example of what $RoboArgs is defined as in Win2019/Powershell5:

PS C:\> echo $RoboArgs
"I:\Fake-directory\Fake-directory\D\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}\Fake\FakeDate" "Z:\Fake-Directory\Fake-Directory\D\{DAFD6721-E854-46F3-B
5CF-7EE1861348A6}\Responses\01182020" /copy:DAT /s /dcopy:DAT /V /log:"I:\FakeDirectory\FakeDirectory\Fake\Logs\Folders_Changed_20200118_21.1
\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}_Responses_01182020.log"

It basically cuts off where the first line ends, and generates the destination in the same manner:

PS C:\> Robocopy "I:\Fake-directory\Fake-directory\D\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}\Fake\FakeDate" "Z:\Fake-Directory\Fake-Directory\D\{DAFD6721-E854-46F3-B
5CF-7EE1861348A6}\Responses\01182020" /copy:DAT /s /dcopy:DAT /V /log:"I:\FakeDirectory\FakeDirectory\Fake\Logs\Folders_Changed_20200118_21.1
\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}_Responses_01182020.log"

2020/01/18 23:17:21 ERROR 123 (0x0000007B) Opening Log File I:\FakeDirectory\FakeDirectory\Fake\Logs\Folders_Changed_20200118_21.1

\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}_Responses_01182020.log
The filename, directory name, or volume label syntax is incorrect.


-------------------------------------------------------------------------------
   ROBOCOPY     ::     Robust File Copy for Windows                              
-------------------------------------------------------------------------------

  Started : Saturday, January 18, 2020 11:17:21 PM
   Source - I:\FakeDirectory\FakeDirectory\Fake\D\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}\Responses\01182020\
     Dest - Z:\FakeDirectory\FakeDirectory\Fake\D\{DAFD6721-E854-46F3-B

Edit 2: Comparing this to Win2008/Powershell4, it actually does the same thing in regards to failing if there's a line break. I think the real problem is how the script is trying to define the source and destination. On 2008/Powershell4, running the script generates everything correctly, with the correct source, destination and log file. Running the exact same script on 2019/Powershell5 seems to generate a problem with how Robocopy is defining these paths, placing both Source, Destination, and Log path all into the source variable, even though that's not how it's defined:

PS C:\> echo $FileSource
FakeDirectory\FakeDirectory\D\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}\Responses\01182020

PS C:\> echo $FileDestination
FakeDirectory\FakeDirectory\D\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}\Responses\01182020

PS C:\> echo $log
/log:"I:\FakeDirectory\FakeDirectory\FakeDirectory\Logs\Folders_Changed_20200118_21.1\{DAFD6721-E854-46F3-B5CF-7EE1861348A6}_Responses_01182020.log"

PS C:\> echo $StandardSwitches
/copy:DAT /s /dcopy:DAT /V