Example: https://en.wikipedia.org/w/index.php?title=User:AntiCompositeNumber/sandbox2&oldid=945530563
{{Graph:Chart
| width=500
| height=250
| xAxisTitle=Time
| yAxisTitle=Cases
| xType=date
| xAxisFormat=%b %-e
| legend=Legend
| type=line
| x=2020-03-06,2020-03-07,2020-03-08,2020-03-09,2020-03-10,2020-03-11,2020-03-12,2020-03-13
| y1Title=Total cases
| y1=8,13,28,41,92,95,108,123
| y2Title=Biogen
| y2=,,,,70,77,82,94
| y3Title=Travel-related
| y3=,,,,4,4,5,5
| y4Title=Berkshire Medical Center
| y4=,,,,,,8,8
| y5Title=Under investigation
| y5=,,,,18,14,13,16
}}produces a rendered output of
which has duplicate x-axis labels. Switching the dates to plain numbers (and removing the associated formatting and typing) renders as expected. Both graphs render as expected in the SVG preview.
