The reason for the lack of parallelism of the lines may be the use of a logarithmic price scale.
In linear mode, the distance between the marks on the price scale is always the same, and the cloned lines are displayed in parallel.
On the logarithmic scale, the apparent distance between adjacent marks is proportional to the logarithm of the ratio of their values, therefore, it differs in different parts of the logarithmic scale.
When you move a line vertically on a chart with a logarithmic price scale, the actual length of the line is saved, but it can change visually due to the various steps of the price scale in different sections.
Since the length of the vertical projection of the line, when moved vertically, changes, and the length of the horizontal projection remains unchanged, the angle of inclination of the line changes as .
A similar situation occurs when cloning a line on a logarithmic scale: if the cloned line is shifted vertically relative to the original, their slope angles will differ. Accordingly, they will not be parallel.