There is an inconsistency between the plot borders on a bar2d and column2d chart which has become apparent with the 3.18.0 release.
With a column2d chart the bottom border of each column didn't exist because there was a x-axis
With a bar2d chart the left border of each bar is present, even if there is a y-axis
This also doesn't occur with a stacked 2d bar chart.,
This jsFiddle demonstrates the issue. The column chart is fine, the bar chart is not.
https://jsfiddle.net/1d27n9ha/3/