new measure is breaking links

[habaholic]

I have some simple excel sheets (one for each month) to track early employee turnover. I have two columns I am using to calculate employee retention. 

Column 1 (Hired in last 6 months)                                Column 2 (Left in last six months)

                             1                      

                              1

                              1                                                                              1

                               1

Then in Power BI I create a new measure Measure = (DIVIDE(SUM(January[Left in first 6 months]) , SUM(January[Hired in last 6 months]))

This gives me 25%. However, I want to show 75% retention. 

So I add "1 -" to my measure,  Measure = 1 - (DIVIDE(SUM(January[Left in first 6 months]) , SUM(January[Hired in last 6 months]))

When I do this it seems to break my links between my data tables and my Date Table, as the bar graph shows all months with the same value.

How can I avoid breaking these links?

[v-chuncz-msft]

@habaholic,

Show us a complete exmaple so that we could have a test.