VoiceOver accessibilityValueDescription does not work properly in NSTableView

I have a Mac application.

I have implemented VoiceOver accessibility text for NSTableView cell as follows in viewForTableColumn delegate method:

cell.textField.accessibilityValueDescription = <Some_Text>;

I get VoiceOver audible output as <Some_Text> only when user navigates to the cell from different column (using Left / Right arrow keys).

But, when user navigates to the cell from same column (using Left / Right arrow keys), I get VoiceOver audible output as the actual text value of cell.

Can anyone please let me know how can I get the proper audible output when user navigates to the cell from same column.