Review Activity / Line Manager Issues

Hope i've put this in the right place, not really a Cireson issue more of a SCSM / Ad Connector issue.

Backstory: Some of our staff log tickets that have line manager review activities attached to the template, we notice that some line managers aren't getting populated in the review activity, but just for a subset of people.

Upon investigation, it seems that its users that have moved department or changed line manager, when I get relationship objects of class UserManagesUser the affected people have more than 1 related object, the old manager and the new manager. I would have thought this shouldn't be the case / cause issue but it does.

Anyway I wrote a quick script to fetch and remove the old line manager relationship object from the users which does solve the issue but was wondering if there's something we're doing wrong / can do to fix - any help appreciated, thanks!

Script to check individual user and then a section to cycle through all affected users and remove the oldest relationship object:

Import-Module SMLets
$smdefaultcomputer = "azrscsm19-01.v1.com"

##Checking for Singular Duplicate Manager of Employee::##
$usertocheck = "lloyda"
$User = Get-SCSMObject -Class (Get-SCSMClass -Name System.Domain.User) -filter "Username -eq '$($usertocheck)"
$UserManagesUser = Get-SCSMRelationshipClass -Name UserManagesUser
$Manager = (Get-SCSMRelationshipObject -ByTarget $User | ?{$_.RelationshipId -eq $UserManagesUser.Id}).SourceObject
$Manager
####

##Cycling through all relationships and finding users with more than one manager relationship assigned.. and nerfing the old ones...
$UserManagesUser = Get-SCSMRelationshipClass -Name UserManagesUser
$AllRels = Get-SCSMRelationshipObject -Relationship $UserManagesUser
$GroupedRels = $AllRels | Group-Object -Property TargetObject
$MoreThanOneManager = $GroupedRels | ?{$_.Count -gt 1}
foreach($group in $MoreThanOneManager){
    $sorted = $group.group | Sort-Object -Property LastModified -Descending
    for($i=1; $i -lt $sorted.count; $i++){
        Remove-SCSMRelationShipObject -SMObject $sorted[$i] -verbose
    }
}