Error 1904 - sometimes

[AlexanderBB]

Attempting to write a Comment with

Sub WriteComment(r as Range, T)
with r
 if not .Comment is Nothing Then
.comment.Delete
end if
.addComment T
end with
End Sub

And I call this with

Dim CRange as Range
Set CRange = WorkSheets(SheetName).cells(RowNumber,ColoumLetter)
WriteTheComment cRange, theText

It usually works... but is starting to fail with Run Time error 1004 Application-defined or object-defined error.

Is there any known reason for this?

 

[AlexanderBB]

I may have a solution, but not a reason.
It works with .addComment Cstr(T)

Even though Vartype(T) is 8.
Isn't that a bit odd?