I have about a dozen (x,y) pairs in a Scatter trace using the offline Python API. The “markers” mode behaves as expected, but if I use the “lines+markers” mode, it not only plots a line connecting x-adjacent points as you’d expect, but also a line from the first point to the last. Here’s what the connecting line looks like:
I haven’t found anything so far in the Python API docs that would explain this, so any insight into what could cause this would be welcome.