Subscript out of range error for dynamic array

I am trying to loop through columns in an array, check if the values are unique, and then count the number of times a given string appears in the array.

Any time I pass a UBound or LBound command I get

subscript out of range

Asterisks are comments for this post and not in code.

*code snippet that is having issue

Dim uniqueValues() As Variant
Dim occurrences() As Variant
Dim partNumber As String
Dim partNumberRange As Range
                
Erase uniqueValues
Erase occurrences
                
Dim tempVar1 As String
Dim tempVar2 As String
Dim j As Long
Dim k As Long

'*fastenerSheets array is defined elsewhere                
Set partNumberRange = fastenerSheets(i - 1).Range("A2", "A" & CStr(diameterTestCount(i - 1) + 1))
Debug.Print partNumberRange.Address
                
Dim cell As Variant
For Each cell In partNumberRange
    partNumber = cell.value
    Debug.Print partNumber
    If IsInArray(partNumber, uniqueValues) Then
        ' If yes, find its index and increment the occurrences
        For j = LBound(uniqueValues) To UBound(uniqueValues)
            If uniqueValues(j) = partNumber Then
                Debug.Print uniqueValues(j)
                occurrences(j) = occurrences(j) + 1
                Exit For
            End If
        Next j
    Else
        ' If no, add the value to uniqueValues and set occurrences to 1

        '*code fails here trying to assign value k
        k = UBound(uniqueValues) + 1
        ReDim Preserve uniqueValues(1 To k)
        ReDim Preserve occurrences(1 To k)
        uniqueValues(k) = partNumber
        occurrences(k) = 1
    End If
Next cell

*function that is called in the snippet

Function IsInArray(val As Variant, arr As Variant) As Boolean
    Dim element As Variant
    On Error Resume Next
    IsInArray = (UBound(Filter(arr, val)) > -1)
    On Error GoTo 0
End Function