You might have already noticed this issue while updating the views module. You know, views module added some configurable options. One of the additions is ‘Do not rewrite if empty’ checkbox on fields’ configuration block. By default, this setting is checked.
Say, you had set an empty text for a field earlier. After views update ‘Do not rewrite if empty’ checkbox is added and checked by default. Hence, the field will not be rewritten to your ‘empty text’. That is, if the field is empty, the empty text will not be displayed. So, to make it working uncheck it and save.