If you have Option Explicit at the top of your code pane you should be getting a “Compile Error” variable not defined on ContentControl.If you don’t then you must be getting a run-time error “424” on the If .Title = “Grade” Then line.
That, or there is more to your code than meets to the eye.
You mention bookmark BM2 in your post but there is no reference to a bookmark named “BM2” or anything else related to a bookmark in your code.
Code:
Private Sub Paragraph_Addition()
Dim strDetails As String
Dim oCC As ContentControl
Dim oRng As Range
Set oCC = ActiveDocument.SelectContentControlsByTitle("Grade").Item(1)
Select Case oCC.Range.Text
Case "LOW"
strDetails = "Please delete all content for Benchmark team."
Case Else
strDetails = vbNullString
End Select
'Write to bookmark
If ActiveDocument.Bookmarks.Exists("BM2") Then
Set oRng = ActiveDocument.Bookmarks("BM2").Range
oRng.Text = strDetails
ActiveDocument.Bookmarks.Add "BM2", oRng
End If
End Sub