Realtick chart problem

Why is it that when you try to make one-day charts of certain indices (BKX for example), it always comes out as a 2-day chart?
Sometimes this resolves itself towards the middle of the day, but today the problem continued throughout the session. Can those that should know fix this?

 

in the chart scaling window, try clicking on Snap to Date Range.

 

Thanks, I'll give that a try.