diff --git a/shifts.ps1 b/shifts.ps1
index 589a243..fea567c 100644
--- a/shifts.ps1
+++ b/shifts.ps1
@@ -335,8 +335,14 @@ try {
                         Write-Debug("{0} {1}: yesterday was Tuesday number {3}, planning RLCZ maintenance shift" -f $dayDate.Date, $dayDate.DayOfWeek, $email, $tuesdaynumber)
                         $rlcz_starttime = $dateEnd.AddHours(1)
                         $rlcz_endtime = $rlcz_starttime.AddHours($rlcz_maintenance_length)
-                        $newshift = Set-Shift -userId $userId -groupID $group.id -shiftName "RLCZ" -StartDate $rlcz_starttime -EndDate $rlcz_endtime -color "yellow" -teamID $team.id -mail $email
-                        $allshifts += [Object[]] $newshift
+                        $rlcz_shifts = [Object[]] $allshifts | Where-Object -Filter { $_.schedulingGroupId -eq $group.Id -and $_.SharedShift.Notes -eq "RLCZ" -and ($_.SharedShift.StartDateTime.ToString("yyyy-MM-dd HH:mm") -eq $rlcz_starttime.ToString("yyyy-MM-dd HH:mm") -and $_.SharedShift.EndDateTime.ToString("yyyy-MM-dd HH:mm") -eq $rlcz_endtime.ToString("yyyy-MM-dd HH:mm")) }
+                        if(Invoke-HasShift -UID $userId -shifts $rlcz_shifts -mail $email) {
+                            Write-Debug("{0} {1}: RLCZ maintenance shift is already set for {2}" -f $dayDate.Date, $dayDate.DayOfWeek, $email)
+                        }
+                        else {
+                            $newshift = Set-Shift -userId $userId -groupID $group.id -shiftName "RLCZ" -StartDate $rlcz_starttime -EndDate $rlcz_endtime -color "yellow" -teamID $team.id -mail $email
+                            $allshifts += [Object[]] $newshift
+                        }
                     }
                 }
             }