You may think you have already connected everything, but look closely again. I have encountered a few similar errors, and often it is caused by some 'stray' lines that are hidden behind some objects or lines on the canvas.

Here are some tips:

Try shifting each step to see if you missed out anything. If the lines are connected to the step properly, moving the step will cause the lines to shift as well. The line that did not shift usually is the one that is not connected to anything.

If you have steps that have multiple lines connecting and converging into it, check the step and lines again. I once encountered a case where the 'stray' line is hiding behind another line that leads to the same step. The 'stray' line is just a few millimeters from properly connected to the step.

Hi Dabuskol,

Can you include a screenshot of your full workflow? Perhaps some extra eyes can spot the line in question.

-Jean