I am getting a Compile error: Member already exists in an object module from which this object module derives'
Bellow is the calling event code and the Form code:

Sub CopyMatchingValues()
    Dim OvertimeSheet As Worksheet
    Dim OTFormSheet As Worksheet
    Dim OvertimeRange As Range
    Dim OTFormRange As Range
    Dim OvertimeCell As Range
    Dim OTFormCell As Range
    Dim LastRow As Long
    Dim i As Long
    Dim matchCount As Long
    Dim calledCopyMatchingXValues As Boolean ' variable to track if 'CopyMatchingXValues' was called
' Create an instance of the UserForm
    Dim StaffForm As New StaffForm1
    ' Show the UserForm as a modal dialog
    StaffForm.Show vbModal
    ' Check if UserForm was submitted or canceled
    If StaffForm.IsSubmitted Then
        ' Retrieve values from the UserForm
        Dim FullName As String
        Dim JobTitle As String
        Dim ContType As String
        Dim WorkHrs As String
        ' UserForm Values
        FullName = StaffForm.FullName.Text
        JobTitle = StaffForm.JobTitle.Text
        ContType = StaffForm.ContType.Text
        WorkHrs = StaffForm.WorkHrs.Text
        ' Copy values from the UserForm to 'OTForm' sheet
        ThisWorkbook.Sheets("OTForm").Range("B4").Value = FullName
        ThisWorkbook.Sheets("OTForm").Range("B7").Value = JobTitle
        ThisWorkbook.Sheets("OTForm").Range("E4").Value = ContType
        ThisWorkbook.Sheets("OTForm").Range("E5").Value = WorkHrs
    Else
        Exit Sub
    End If
    
    Set OvertimeSheet = ThisWorkbook.Sheets("Overtime")
    On Error Resume Next
    Set OvertimeRange = Application.InputBox("Select range in column C", Type:=8)
    On Error GoTo 0
    If OvertimeRange Is Nothing Or Not OvertimeRange.Columns(1).Column = 3 Then
        MsgBox "No valid range selected in column C.", vbCritical
        Exit Sub
    End If
    Set OTFormSheet = ThisWorkbook.Sheets("OTForm")
    Set OTFormRange = OTFormSheet.Range("B4")
    LastRow = 11
    matchCount = 0
    calledCopyMatchingXValues = False ' initialize to False
    
    For Each OvertimeCell In OvertimeRange
        If OvertimeCell.Value = OTFormRange.Value Then
            matchCount = matchCount + 1
            If matchCount > 11 Then
                calledCopyMatchingXValues = True ' set to True if 'CopyMatchingXValues' is called
                Exit For
            End If
            OTFormSheet.Cells(LastRow, "D").Value = OvertimeCell.Offset(0, 28).Value
            OTFormSheet.Cells(LastRow, "C").Value = OvertimeCell.Offset(0, 27).Value
            OTFormSheet.Cells(LastRow, "B").Value = OvertimeCell.Offset(0, 1).Value
            OTFormSheet.Cells(LastRow, "A").Value = OvertimeCell.Offset(0, -2).Value
            LastRow = LastRow + 1
        End If
    Next OvertimeCell
    
    If calledCopyMatchingXValues Then ' only clear the values if 'CopyMatchingXValues' was called
        OTFormSheet.Range("D11:D" & LastRow - 1).ClearContents
        OTFormSheet.Range("C11:C" & LastRow - 1).ClearContents
        OTFormSheet.Range("B11:B" & LastRow - 1).ClearContents
        OTFormSheet.Range("A11:A" & LastRow - 1).ClearContents
    End If
    
    If matchCount > 11 Then
        Call CopyMatchingXValues
        Exit Sub
    End If
    
    OTFormSheet.Range("I24").Value = Date
    OTFormSheet.Range("I25").Value = Date
    Dim message As String
    message = OTFormSheet.Range("B4").Value & "'s overtime dates have been entered"
    MsgBox message, vbInformation, "OVERTIME ENTRY"
    ThisWorkbook.Sheets("OTForm").Activate
End Sub

Private Sub StaffSubmit()
    ' Check if all text boxes are filled
    If FullName.Text = "" Or JobTitle.Text = "" Or ContType.Text = "" Or WorkHrs.Text = "" Then
        MsgBox "Please fill in all the fields.", vbExclamation
        Exit Sub
    End If
    ' Copy values from text boxes to 'OTForm' sheet
    ThisWorkbook.Sheets("OTForm").Range("B4").Value = FullName.Text
    ThisWorkbook.Sheets("OTForm").Range("B7").Value = JobTitle.Text
    ThisWorkbook.Sheets("OTForm").Range("E4").Value = ContType.Text
    ThisWorkbook.Sheets("OTForm").Range("E5").Value = WorkHrs.Text
    ThisWorkbook.Sheets("OTForm").Range("B4").Calculate
    ThisWorkbook.Sheets("OTForm").Range("B7").Calculate
    ThisWorkbook.Sheets("OTForm").Range("E4").Calculate
    ThisWorkbook.Sheets("OTForm").Range("E5").Calculate
    ThisWorkbook.Sheets("OTFormX").Range("B4").Calculate
    ThisWorkbook.Sheets("OTFormX").Range("B7").Calculate
    ThisWorkbook.Sheets("OTFormX").Range("E4").Calculate
    ThisWorkbook.Sheets("OTFormX").Range("E5").Calculate
    ' Close the UserForm
    Unload Me
End Sub