Joining Date Dimension with Calculated Value

I am having issues with a join on the date dimension with one of the calculated value .

Here is my use case.

I have two transaction table and one date dimenion table in my model
I have to pick the dates in this order

Table A.Date 1
Table A.Date 2

Table B.Date 3
Table B.Date 4

Step 1

In Table A ,

I created a calculated Value "Date1TabA" as

DateXTabA = COALESCE('Table A'[Date 1], 'Table A'[Date 2])

Step 2

In Table B ,

I created a calculated Value "Date1TabARelated" as

Date1TabARelated = RELATED('Table A'[DateXTabA])

DateYTabB = COALESCE('Table B'[Date 3], 'Table A'[Date 4])

DateStart = COALESCE('Table B'[DateXTabA], 'Table B'[DateYTabB])

Step 3

I have a one to many relationship with Date Dimension and Table B on
DateUS = DateStart

I getting blank in FY column from Date Dimension , whenever there is a blank in Table A.Date 1 , even though DateStart has value.

Thanks in Advance.