Investigate an Extra Line in an Excel XY Scatter Chart

Select the affected chart and open Chart Design > Select Data. Select each series and click Edit to inspect its X and Y value ranges. Compare the referenced cells with the intended data, including the point near (0.01029043, -14.0597).

Open Chart Design > Change Chart Type and note the selected XY scatter subtype. Right-click the affected series and choose Format Data Series to inspect its line and marker settings. Record these settings before making changes.

Choose File > New > Blank Workbook and copy only the X and Y values needed to test the affected point. Select those values and use Insert > Scatter (X, Y) to create a chart with the same subtype and series formatting as the original.

In both workbooks, repeat the exact clicks or highlighting actions used when the line appeared. For a point selection, click the series once and then click the individual point. Compare whether the extra line appears under the same conditions.

Start a screen recording before selecting the affected point. Capture the chart before and after the extra line appears, including the sequence of clicks and any data edits or chart extensions.

When the line appears, use File > Save As to save a separate copy of the workbook. Note whether the line remains after clicking outside the chart and whether it returns after closing and reopening the saved copy.

Submit the test workbook and recording through your available Microsoft support channel. Include the Excel version, chart subtype, series ranges, affected coordinates, and whether repeated selection is required. Remove confidential data before sharing, and retest the sanitized file to confirm that it still demonstrates the behavior.