Steps to reproduce

1. Create a Page which has a component like mtk:components\textImage
   and set some content (headline label) on two locales (like en and de) 
2.  Move to Translation app, select the page created on step 1 and export as XLS.
3. Modify the XLS (delete the DE content)
4. Import the XLS again and check it fails

Expected results

The de content (actually null because it was deleted) gets also deleted on JCR

Actual results

The translation file is never imported and the following exception is thrown:

2021-05-04 10:38:17,330 ERROR lation.ui.action.TranslationFileUploadDialogAction: An error occurred when executing the command uploadTranslationFile from catalog translation
java.lang.NullPointerException: null
	at java.text.SimpleDateFormat.parse(SimpleDateFormat.java:1439) ~[?:1.8.0_191]

Workaround

N/A

Development notes

N/A