I am using Tableau 10.5.3. It seems that when a label is "too close" to a row boundary, Tableau forces it to move up or down, which looks odd. Changing the vertical alignment (bottom, middle, top, automatic) has no effect on this.
See the graphic below for examples. The labels of the top bar and bottom bar in each subdivision are too high/low relative to the other ones. There clearly is enough space to align the labels better.
Any suggested solution? Is this only a problem in 10.5.3?
I did try to replicate this issue using Superstore, but its not as evident as your screenshot.
3 things you could try to get a cleaner view:
a. Make the font size smaller by 1 pt.
b. Ensure the Alignment is Automatic
c. Allow labels to overlap other marks is unchecked