This time, no noob question but a noob workaround that I’d like to share, as I didn’t find it anywhere in over two hours of troubleshooting. Hope you are as happy about finding it here as I would have been.
If you create a “XY (scatter)” chart from a pivot table, e. g. in order to get a presentation that preserves linear scales in both dimensions (X and Y), the chart misbehaves as if it couldn’t numerically evaluate the values in the first pivot column, resulting in equidistant X axis lables, regardless of the real X values. There is a bug report on this misbehaviour, but sadly, it’s three years old by now and still not been worked on.
Moreover, the data range of a pivot chart doesn’t even appear to be editable - the option “Data Ranges …” that appears in the context menu of other charts is missing.
I have encountered suggestions to manually copy the data of the pivot table into a plain table elsewhere and create a plain chart based on that table, but the static nature of this workaround, including the need to manually copy the data over and over on every pivot update, feels like a cumbersome limitation to me.