This KB describes the cause of M1 overprint charts with separator lines.
As an operator, I want to create a M1 press profile. M1 overprint charts aren't by default available so I created one in the Overprint Charts library.
When exporting the chart for measuring, I noticed that they have separator lines, while in the Measure Overprint Chart tool there are no separator lines:
PDF of the M1 overprint chart
Measure Overprint Chart tool
Due to a bug in Color Pilot, M1 overprint charts will have separator lines when the measurement condition is set to M0. Make sure that you first switch to the M1 overprint charts BEFORE exporting the overprint charts as PDF.