When adding a line to the "Line and stacked column chart", the line value is also shown in each bar as Blank. The bars are correct when no line is present, i.e. only showing the column values. The behavior occurs in both PBI Desktop and in the service. We use live connection to an on-prem SSAS model. The line is a moving average.
This behavior was not present at July 27th. The latest version of Power BI Desktop was published on July 30th (2.83.5894.961), making it plausible that the issues started with this update.
The issue is not present when I reproduce the chart in PBI Desktop RS.
Hovering over a bar. Note "Column data" in the header.
Hovering over the line. Note the line value.
Hovering over the Blank bar. Note that the tooltip reads "Line data" instead of Column data and that the amount is identical to the line value
The cart reproduced in PBI Desktop RS (January 2020). The Blank bar is not present.