Cell does not react to formatting

Hello,
I have a pivot table that is pulling dates from a source sheet.
The dates in the source sheet are a formula results that is returning a Friday based on the date: [=E2+5-WEEKDAY(E2,2)]. I formatted the result to be shown as a long date.

When creating a pivot chart I select that column to be shown in Rows.
The result that I see for some reason is Month where that Friday is...
I don't understand how to change that "Jan" to ANY other format (short or long date).
Thanks for your help.
UPDATE: Sample sheet is attached.
UPDATE 2: I found how to make it work - go to Analyze - Group sub menu - Ungroup.
This will ungroup dates and will allow you to play with date format.

pivot error.png
sa.png