Is "One chapter for each appended files" really working?

I have 4 MP4 files. Each file has AVC video and AAC audio. I use MKVToolNix GUI version: 31.0.0 to merge them. In particular, I open the GUI and find out that the "multiplexer" tab is already selected. I the "input" tab, I then open my 4 files, and in the bottom "tracks, chapters and tags" box, the 8 streams appear correctly. I then open the "Output" tab, and in the "Generating chapter" textbox, I select "One chapter for each appended files". I then choose a destination file name and click on "Start multiplexing".

In the output file I then would expect 4 chapters, one for each appended file. But -The "Info tool" of MKVToolNix -The "Header" tool of MKVToolNix -MediaInfo version 18.12 All report the output file as containing 8 streams but 1 and only 1 chapter, starting at the start of the file. In fact I wanted to see the different chapters in VLC but it is not possible

Am I using the option incorrectly or is this a bug?