check to see if you have a bunch of "extra" styles....here is a macro called stylekiller.....it removes any non-standard style and takes about 5 minute or so to run...If you think it'll help....

it seems silly but XL sometimes does weird things with styles....HTH

Sub StyleKill()

    Dim styT As Style
    Dim intRet As Integer
    Dim Cntr1 As Single, Cntr2 As Single, TotStyles As Single
    
    Application.DisplayStatusBar = True
    Cntr1 = 1
    Cntr2 = 1

    TotStyles = ActiveWorkbook.Styles.Count
    
    For Each styT In ActiveWorkbook.Styles
        DoEvents
        Application.StatusBar = "Working on: " & Cntr1 & " of " & TotStyles & " Deleted: " & Cntr2
        If Not styT.BuiltIn Then
            styT.Delete
            Cntr2 = Cntr2 + 1
        End If
        Cntr1 = Cntr1 + 1
    Next styT
    
    Application.StatusBar = ""

End Sub