I have encountered a very strange issue and I wanted to get the forum's thoughts on what the problem might be and how to fix it. Over the weekend I wrote Stata code to produce various bar graphs; code that I wrote on my personal copy of Stata on my laptop. Today I copied the working directory to my office workstation to continue working on the code. I casually reran the dofile on my workstation to start where I left off, and noticed that the background grid on the bar graphs now have giant gaps in them! I've attached example output to show what I mean:

Laptop output: Array


Workstation output: Array


Here is the code that produces the figure (the same code was executed on both machines from identical datasets):
Code:
qui sum frac_alldwnlds
graph bar ///
    frac_alldwnlds, over(ep, sort(frac_alldwnlds) desc label(alt tick)) ///
    title("All Downloads of Kids Considered") ///
    subtitle("Each episode's share of 6,833 downloads") ///
    ytitle("Percent (%)") ylabel(0(2)10, glp(dot) glc(grey) angle(horizontal)) ///
    yline(`r(mean)', lpattern(dash)) ///
    lintensity(*-255) name(frac_alldwnlds, replace)  graphr(c(white))
graph export "$figs\frac_alldwnlds.png", as(png) width(1200) replace
The images I have attached are in PNG format, but the graphs look exactly the same in Stata. The only thing that is different is that my laptop has Stata 15.1 and my workstation has Stata/SE 14.2. Could this produce such different output?

NOTE: I reduced the size of the attached PNG files using Paint in Windowsm so they are no longer identical quality. The pictures that are actually output from Stata ARE of identical quality. The only difference is the grid, which can be seen clearly in the attached images.