It is not a rare occurence for the same string is repeated through a document.
Use the Propagate Translation command from the Table menu to copy the translation from the selected rows to other entries in the document sharing the same reference string. This will not propagate to rows with a non-empty translation however. Rows that already have been translated will be left alone.
If you would prefer to see translations propagated automatically every time you edit a string, you can enable that behavior from the preferences.