Answers for "LineOnLineOverlayer thinks the lines are not coincidental but they are."
https://knowledge.safe.com/questions/67137/lineonlineoverlayer-thinks-the-lines-are-not-coinc.html
最新LineOnLineOve回答的问题”rlayer thinks the lines are not coincidental but they are."Answer by erik_jan
https://knowledge.safe.com/answers/67138/view.html
It seems like the coordinates of the smaller parts have been rounded and therefor are not exactly on the original line.
If you are using FME 2018, you can set the tolerance on the LineOnLineOverlayer to Automatic, which will take care of that issue.