X-axis showing wrong date

mtarler 
I actually think I am using a normal line chart, at least that is what it says when I click on "change chart type" to double check.

I'm not entirely sure what you mean when suggesting using a 2-d line? Do you mean an additional series and use this series to plot the x-axis instead of using the build in x-axis?
I thought the fact that I set the start date to an end-of-month-date would automatically make the x-axis using that number. It was a while since I worked with excel, but as I seem to recall it it used to work.