$session.FileExists() always returns true

# Set the path to the file that you want to check for on the SFTP server
$filename = "New"+(Get-Date).ToString("yyyyMMdd")+"*.txt"
# $filename="file.txt"
$filePath = "/directory/"+$filename
# Set the local path where you want to download the file
$localPath = "C:\Users\ristianchrathke\Downloads\"
 
# Load WinSCP .NET assembly
Add-Type -Path "WinSCPnet.dll"
 
# Set up session options
$sessionOptions = New-Object WinSCP.SessionOptions -Property @{
    Protocol = [WinSCP.Protocol]::Sftp
    HostName = $source_host
    UserName = $source_username
    Password = $source_password
    SshHostKeyFingerprint = "xxxxxxxxxxx"
}
 
$session = New-Object WinSCP.Session
$session.Open($sessionOptions)
 
echo "connection established"
 
# Set up a loop to check for the file every 15 minutes
while ($true) {
    # Check if the file exists on the SFTP server
    if ($session.FileExists($filePath)) {
        # Download the file to the specified local path
        $transferResult = $session.GetFiles($filePath, $localPath+"*")
        $transferResult.Check()
        echo "File downloaded"
 
        # Disconnect from the SFTP server
        $session.close()
        echo "session closed"
        # Break out of while loop
        break
    }
    echo "file not found, waiting 15 minutes before next filecheck..."
 
    # Wait for 15 minutes before checking again
    Start-Sleep -Seconds 900
}
 
# Get yesterday's date
$yesterday = (Get-Date).AddDays(-1).ToString("yyyyMMdd")
 
# Rename the downloaded file to "BAI_" followed by yesterday's date
Rename-Item "$localPath\$filename" "New$yesterday.txt"