On my project, only the number of files was displayed on cppncss trend graph. After a bit of investigation and by removing files I realized that the scale was either not automatic or not handling different orders in the values (because the screenshot on cppncss plugin suggest the scale could change).

All the measurements like NCSS, CCN, total functions, CCN violations and NCSS violations are not displayed in my case.

I have attached the picture of my trend graph and the sample file on which it is failing.