The cross-reference to a number range variable refers the paragraph, which contains the number range variable. Text before the variable is named “Category”, text after the variable is named “Caption text”, from the same paragraph. Because the content of each table cell is at least one paragraph and therefore two cells are at least two paragraphs, you cannot have a reference, which contains content from two different cells.
You need to write “Some document” into the same paragraph as “Annex 1” to make it referable by a cross-reference to a number range variable.