I have a dashboard with a few charts that all pull project data from the same portfolio. Each of them has a different custom field for the x-axis (or slices of the donut) and a count of projects for the y-axis. Charts seem to ignore data if there is no field value set in the x-axis field. For example, if I have a portfolio of 10 projects and only 8 of them have a priority field set, then if I make a chart with priority as the x-axis, it will only show 8 data in the chart.
This has led to having slightly mismatched data across charts depending on which projects have different custom fields left empty. It would be really helpful to have a [no value set] value (similar to when you group tasks within a project list). This could even be a toggle that you set on each chart’s options.