Combined chart bar width inconsistency (Bar chart width 1.0 will have thin space between bars)

Using combined chart view I'm trying to display semi transparent bar data with no spacing between the bars, but I'm getting some unexpected behaviour: setting the barWidth of the set to 1.005 gets me chart with bars that start with spacing between them, towards the middle gets perfect and towards the end bars start to overlap and which results of a solid color - a combination of the 2 semi transparent.

Running the same code on smaller screens gets me spacing and on bigger screen - overlap.