Multiple Folders in New-PWScanForReferences -Priority

I am trying to use the New-PWScanForReferences  cmdlet and have it scan multiple Folders to find the references.  The executable wants these separated with a semicolon but this doesn't seem to work.  Per the executable's help, I would also proceed the folder with 'r:' for recursive, but this also does not work and appears to need the -RecursePriority.  It seems a trailing backslash is needed even though the help for the executable does not have this requirement.

From the executable's help:

For example, the combination of:
-masterfolders "Top level folder 3" -masterfolders "Top level folder 1;Top level folder 2"
is equivalent to:
-masterfolders "Top level folder 3;Top level folder 1;Top level folder 2"

My code is:

$myPriority = 'Folder 1\subfolder\;Folder 2\;Folder 3\'

$NewScanRef = @{
DataSourceName = 'myDatasource';
UserName = 'myUserName';
Password = 'mypassword;
ScanMode = 'references;linksets';
MasterDocuments = '{' + $myDocumentGUID + '}';
Priority = $myPriority;
#Proximity = 'r:1';
Order = 'priority;proximity';
#Applications = '';
LogFilePath = $myLogpath ;
New-PWScanForReferences @NewScanRef -RecurseMasterFolders -RecursePriority

I have also tried using 

$myPriority = @("Folder 1\subfolder\","Folder 2\","Folder 3\")


$myPriority = "Folder 1\subfolder\","Folder 2\","Folder 3\"

With no success.  What am I missing?