I'm plotting different values from a simulation software. In my excel plots I have 6 data series, 3 of the are just reference values which I don't want to show up in the legend. When I delete these series from the legends everything seems to work fine, but when I save and re-open or copy/paste to Powerpoint the legends I deleted show up again. There is still only three legends, but it seems to be random which ones it is. What is the problem here?

Any help is much appreciated.