@Amjad_Sahi
I think there has been a difference in our understanding of the issue as I can still see the issue in the attached file that you sent.
The issue is that one of the bars of the graph is missing not the whole bar graph chart.
Also, the number of bars of the graph is also varying even though both of the exported file was generated from same template with same data. You can refer by comparing the following attached files.
This is the screen shot that I took from your attached file. oneBarMissing.png (26.1 KB)
While the actual output should have been allBars.png (28.4 KB)